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Număr minim de ștergeri și inserări pentru a transforma un șir în altul

Date două șiruri s1 şi s2 . Sarcina este să elimina/sterge şi introduce cel număr minim de caractere din s1 să-l transforme în s2 . Ar putea fi posibil ca acelasi personaj trebuie eliminat/șters dintr-un punct al s1 și introdus în alt punct.

Exemplul 1:  

Intrare: s1 = „grămadă” s2 =
Ieșire: 3
Explicaţie: Ștergere minimă = 2 și inserție minimă = 1
p și h sunt șterse din heap și apoi p este inserat la început. Un lucru de remarcat, deși p a fost necesar, a fost eliminat/șters mai întâi din poziția sa și apoi a fost inserat într-o altă poziție. Astfel p contribuie cu unul la numărul de ștergere și unul la numărul de inserții.



Intrare: s1 = 'geeksforgeeks' s2 = 'geeks'
Ieșire: 8
Explicaţie: 8 ștergeri, adică eliminați toate caracterele șirului „forgeeks”.

Cuprins

Folosind recursiunea - O(2^n) Timp și O(n) Spațiu

O abordare simplă pentru a rezolva problema presupune generarea tuturor subsecvente de s1 și pentru fiecare subsecvență calculând a minim ștergeri și inserții necesare pentru a-l transforma în s2. O abordare eficientă folosește conceptul de cea mai lungă secvență comună (LCS) pentru a găsi lungimea celui mai lung LCS. Odată ce avem LCS de două șiruri, putem găsi Inserție minimă şi Ștergeri pentru a converti s1 în s2.

  • La minimizați ștergerile trebuie doar să eliminăm caractere din s1 care nu fac parte din cea mai lungă secvență comună (LCS) cu s2 . Acest lucru poate fi determinat de scăzând cel lungime LCS din lungimea de s1 . Astfel, numărul minim de ștergeri este:
    minDeletions = lungimea s1 - lungimea LCS.
  • Similar cu minimizați inserțiile trebuie doar să inserăm caractere din s2 în s1 care nu fac parte din LCS. Acest lucru poate fi determinat de scăzând cel lungime LCS din lungimea de s2 . Astfel, numărul minim de inserții este:
    minInsertions = lungimea s2 - lungimea LCS.
C++
// C++ program to find the minimum number of insertion and deletion // using recursion. #include    using namespace std; int lcs(string &s1 string &s2 int m int n) {    // Base case: If either string is empty  // the LCS length is 0  if (m == 0 || n == 0)  return 0;  // If the last characters of both substrings match  if (s1[m - 1] == s2[n - 1])  // Include the matching character in LCS and   // recurse for remaining substrings  return 1 + lcs(s1 s2 m - 1 n - 1);  else  // If the last characters do not match   // find the maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  return max(lcs(s1 s2 m n - 1) lcs(s1 s2 m - 1 n)); } int minOperations(string s1 string s2) {  int m = s1.size();  int n = s2.size();  // the length of the LCS for s1[0..m-1]  // and s2[0..n-1]  int len = lcs(s1 s2 m n);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s1  int minInsertions = n - len;  // Total operations needed  int total = minDeletions + minInsertions;  return total; } int main() {  string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  cout << res;  return 0; } 
Java
// Java program to find the minimum number of insertions and // deletions using recursion. class GfG {    static int lcs(String s1 String s2 int m int n) {    // Base case: If either string is empty the LCS  // length is 0  if (m == 0 || n == 0) {  return 0;  }  // If the last characters of both substrings match  if (s1.charAt(m - 1) == s2.charAt(n - 1)) {  // Include the matching character in LCS  // and recurse for remaining substrings  return 1 + lcs(s1 s2 m - 1 n - 1);  }  else {    // If the last characters do not match  // find the maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  return Math.max(lcs(s1 s2 m n - 1)  lcs(s1 s2 m - 1 n));  }  }  static int minOperations(String s1 String s2) {  int m = s1.length();  int n = s2.length();  // the length of LCS for s1[0..m-1] and  // s2[0..n-1]  int len = lcs(s1 s2 m n);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s2  int minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions;  }  public static void main(String[] args) {  String s1 = 'AGGTAB';  String s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  System.out.println(res);  } } 
Python
# Python program to find the minimum number of insertions # and deletions using recursion def lcs(s1 s2 m n): # Base case: If either string is empty # the LCS length is 0 if m == 0 or n == 0: return 0 # If the last characters of both substrings match if s1[m - 1] == s2[n - 1]: # Include the matching character in LCS and  # recurse for remaining substrings return 1 + lcs(s1 s2 m - 1 n - 1) else: # If the last characters do not match  # find the maximum LCS length by: # 1. Excluding the last character of s1 # 2. Excluding the last character of s2 return max(lcs(s1 s2 m n - 1) lcs(s1 s2 m - 1 n)) def minOperations(s1 s2): m = len(s1) n = len(s2) # the length of LCS for s1[0..m-1] and s2[0..n-1] lengthLcs = lcs(s1 s2 m n) # Characters to delete from str1 minDeletions = m - lengthLcs # Characters to insert into str1 minInsertions = n - lengthLcs # Total operations needed return minDeletions + minInsertions if __name__ == '__main__': s1 = 'AGGTAB' s2 = 'GXTXAYB' result = minOperations(s1 s2) print(result) 
C#
// C# program to find the minimum number of insertions and // deletions using recursion. using System; class GfG {  static int lcs(string s1 string s2 int m int n) {    // Base case: If either string is empty the LCS  // length is 0  if (m == 0 || n == 0)  return 0;  // If the last characters of both substrings match  if (s1[m - 1] == s2[n - 1]) {    // Include the matching character in LCS  // and recurse for remaining substrings  return 1 + lcs(s1 s2 m - 1 n - 1);  }  else {    // If the last characters do not match  // find the maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  return Math.Max(lcs(s1 s2 m n - 1)  lcs(s1 s2 m - 1 n));  }  }  static int minOperations(string s1 string s2) {  int m = s1.Length;  int n = s2.Length;  // the length of LCS for s1[0..m-1] and  // s2[0..n-1]  int lengthLcs = lcs(s1 s2 m n);  // Characters to delete from s1  int minDeletions = m - lengthLcs;  // Characters to insert into s2  int minInsertions = n - lengthLcs;  // Total operations needed  return minDeletions + minInsertions;  }  static void Main(string[] args) {  string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int result = minOperations(s1 s2);  Console.WriteLine(result);  } } 
JavaScript
// JavaScript program to find the minimum number of // insertions and deletions using recursion function lcs(s1 s2 m n) {  // Base case: If either string is empty the LCS length  // is 0  if (m === 0 || n === 0) {  return 0;  }  // If the last characters of both substrings match  if (s1[m - 1] === s2[n - 1]) {    // Include the matching character in LCS and recurse  // for remaining substrings  return 1 + lcs(s1 s2 m - 1 n - 1);  }  else {    // If the last characters do not match find the  // maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  return Math.max(lcs(s1 s2 m n - 1)  lcs(s1 s2 m - 1 n));  } } function minOperations(s1 s2) {  const m = s1.length;  const n = s2.length;  // Length of the LCS  const len = lcs(s1 s2 m n);  // Characters to delete from s1  const minDeletions = m - len;  // Characters to insert into s1  const minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions; } const s1 = 'AGGTAB'; const s2 = 'GXTXAYB'; const res = minOperations(s1 s2); console.log(res); 

Ieșire
5

Folosind DP de sus în jos (Memoization) - O(n^2) Timp și O(n^2) Spațiu

În această abordare aplicăm memorare pentru a stoca rezultatele subproblemelor suprapuse în timp ce se găsește cea mai lungă subsecvență comună (LCS). O matrice 2D memoriu este folosit pentru a salva LCS lungimi pentru diferite subșiruri ale celor două șiruri de intrare asigurând că fiecare subproblema este rezolvată o singură dată.
Această metodă este similară cu Cea mai lungă subsecvență comună (LCS) problemă cu utilizarea memorizării.

C++
// C++ program to find the minimum of insertion and deletion // using memoization. #include    #include  using namespace std; int lcs(string &s1 string &s2 int m int n   vector<vector<int>> &memo) {    // Base case: If either string is empty the LCS length is 0  if (m == 0 || n == 0)  return 0;  // If the value is already computed return  // it from the memo array  if(memo[m][n]!=-1)  return memo[m][n];    // If the last characters of both substrings match  if (s1[m - 1] == s2[n - 1])    // Include the matching character in LCS and recurse for  // remaining substrings  return memo[m][n] = 1 + lcs(s1 s2 m - 1 n - 1 memo);  else    // If the last characters do not match find the maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  return memo[m][n] = max(lcs(s1 s2 m n - 1 memo)  lcs(s1 s2 m - 1 n memo)); } int minOperations(string s1 string s2) {    int m = s1.size();   int n = s2.size();     // Initialize the memoization array with -1.  vector<vector<int>> memo = vector<vector<int>>  (m+1vector<int>(n+1-1));    // the length of the LCS for   // s1[0..m-1] and s2[0..n-1]  int len = lcs(s1 s2 m n memo);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s1  int minInsertions = n - len;  // Total operations needed  int total = minDeletions + minInsertions;  return total; } int main() {    string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  cout << res;  return 0; } 
Java
// Java program to find the minimum of insertion and deletion // using memoization. class GfG {  static int lcs(String s1 String s2 int m int n int[][] memo) {    // Base case: If either string is empty   // the LCS length is 0  if (m == 0 || n == 0) {   return 0;  }  // If the value is already computed return it  // from the memo array  if (memo[m][n] != -1) {  return memo[m][n];  }  // If the last characters of both substrings match  if (s1.charAt(m - 1) == s2.charAt(n - 1)) {  // Include the matching character in LCS and recurse for  // remaining substrings  memo[m][n] = 1 + lcs(s1 s2 m - 1 n - 1 memo);  }  else {    // If the last characters do not match  // find the maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  memo[m][n] = Math.max(lcs(s1 s2 m n - 1 memo)  lcs(s1 s2 m - 1 n memo));  }  return memo[m][n];  }  static int minOperations(String s1 String s2) {    int m = s1.length();   int n = s2.length();   // Initialize the memoization array with -1   // (indicating uncalculated values)  int[][] memo = new int[m + 1][n + 1];  for (int i = 0; i <= m; i++) {  for (int j = 0; j <= n; j++) {  memo[i][j] = -1;  }  }  // the length of LCS for s1[0..m-1] and s2[0..n-1]  int len = lcs(s1 s2 m n memo);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s1  int minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions;  }  static void main(String[] args) {    String s1 = 'AGGTAB';   String s2 = 'GXTXAYB';   int res = minOperations(s1 s2);   System.out.println(res);   } } 
Python
# Python program to find the minimum number of insertions and  # deletions using memoization def lcs(s1 s2 m n memo): # Base case: If either string is empty the LCS length is 0 if m == 0 or n == 0: return 0 # If the value is already computed  # return it from the memo array if memo[m][n] != -1: return memo[m][n] # If the last characters of both substrings match if s1[m - 1] == s2[n - 1]: # Include the matching character in LCS and  # recurse for remaining substrings memo[m][n] = 1 + lcs(s1 s2 m - 1 n - 1 memo) else: # If the last characters do not match  # find the maximum LCS length by: # 1. Excluding the last character of s1 # 2. Excluding the last character of s2 memo[m][n] = max(lcs(s1 s2 m n - 1 memo) lcs(s1 s2 m - 1 n memo)) # Return the computed value return memo[m][n] def minOperations(s1 s2): m = len(s1) n = len(s2) # Initialize the memoization array with -1 # (indicating uncalculated values) memo = [[-1 for _ in range(n + 1)] for _ in range(m + 1)] # Calculate the length of LCS for s1[0..m-1] and s2[0..n-1] lengthLcs = lcs(s1 s2 m n memo) # Characters to delete from s1 minDeletions = m - lengthLcs # Characters to insert into s1 minInsertions = n - lengthLcs # Total operations needed return minDeletions + minInsertions if __name__ == '__main__': s1 = 'AGGTAB' s2 = 'GXTXAYB' res = minOperations(s1 s2) print(res) 
C#
// C# program to find the minimum of insertion and deletion // using memoization. using System; class GfG {    static int lcs(string s1 string s2 int m int n  int[ ] memo) {    // Base case: If either string is empty the LCS  // length is 0  if (m == 0 || n == 0) {  return 0;  }  // If the value is already computed return it from  // the memo array  if (memo[m n] != -1) {  return memo[m n];  }  // If the last characters of both substrings match  if (s1[m - 1] == s2[n - 1]) {    // Include the matching character in LCS and  // recurse for remaining substrings  memo[m n]  = 1 + lcs(s1 s2 m - 1 n - 1 memo);  }  else {    // If the last characters do not match find the  // maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  memo[m n]  = Math.Max(lcs(s1 s2 m n - 1 memo)  lcs(s1 s2 m - 1 n memo));  }  // Return the computed value  return memo[m n];  }    static int minOperations(string s1 string s2) {    int m = s1.Length;   int n = s2.Length;   // Initialize the memoization array with -1  // (indicating uncalculated values)  int[ ] memo = new int[m + 1 n + 1];  for (int i = 0; i <= m; i++) {  for (int j = 0; j <= n; j++) {  memo[i j] = -1;  }  }  // Calculate the length of LCS for s1[0..m-1] and  // s2[0..n-1]  int lengthLcs = lcs(s1 s2 m n memo);  // Characters to delete from s1  int minDeletions = m - lengthLcs;  // Characters to insert into s1  int minInsertions = n - lengthLcs;  // Total operations needed  return minDeletions + minInsertions;  }    static void Main(string[] args) {    string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  Console.WriteLine(res);   } } 
JavaScript
// JavaScript program to find the minimum number of // insertions and deletions using memoization function lcs(s1 s2 m n memo) {  // Base case: If either string is empty the LCS length  // is 0  if (m === 0 || n === 0) {  return 0;  }  // If the value is already computed return it from the  // memo array  if (memo[m][n] !== -1) {  return memo[m][n];  }  // If the last characters of both substrings match  if (s1[m - 1] === s2[n - 1]) {    // Include the matching character in LCS and recurse  // for remaining substrings  memo[m][n] = 1 + lcs(s1 s2 m - 1 n - 1 memo);  }  else {    // If the last characters do not match find the  // maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  memo[m][n] = Math.max(lcs(s1 s2 m n - 1 memo)  lcs(s1 s2 m - 1 n memo));  }    return memo[m][n]; } function minOperations(s1 s2){  const m = s1.length;  const n = s2.length;  // Initialize the memoization array with -1 (indicating  // uncalculated values)  const memo = Array.from({length : m + 1}  () => Array(n + 1).fill(-1));  // Calculate the length of LCS for s1[0..m-1] and  // s2[0..n-1]  const len = lcs(s1 s2 m n memo);  // Characters to delete from s1  const minDeletions = m - len;  // Characters to insert into s1  const minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions; } const s1 = 'AGGTAB'; const s2 = 'GXTXAYB'; const res = minOperations(s1 s2); console.log(res); 

Ieșire
5

Folosind DP de jos în sus (tabulare) - O(n^2) Timp și O(n^2) Spațiu

Abordarea este similară cu cea precedentul doar în loc să distrugă problema recursiv noi iterativ construiți soluția calculând în de jos în sus mod. Mentinem a tabel 2D dp[][] astfel încât dp[i][j] stochează Cea mai lungă subsecvență comună (LCS) pentru subproblema (i j) .
Această abordare este similară cu găsirea LCS în mod de jos în sus .

C++
// C++ program to find the minimum of insertion and deletion // using tabulation. #include    #include  using namespace std;   int lcs(string &s1 string &s2) {    int m = s1.size();  int n = s2.size();  // Initializing a matrix of size (m+1)*(n+1)  vector<vector<int>> dp(m + 1 vector<int>(n + 1 0));  // Building dp[m+1][n+1] in bottom-up fashion  for (int i = 1; i <= m; ++i) {  for (int j = 1; j <= n; ++j) {  if (s1[i - 1] == s2[j - 1])  dp[i][j] = dp[i - 1][j - 1] + 1;  else  dp[i][j] = max(dp[i - 1][j] dp[i][j - 1]);  }  }  // dp[m][n] contains length of LCS for s1[0..m-1]  // and s2[0..n-1]  return dp[m][n]; } int minOperations(string s1 string s2) {    int m = s1.size();  int n = s2.size();  // the length of the LCS for  // s1[0..m-1] and s2[0..n-1]  int len = lcs(s1 s2);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s1  int minInsertions = n - len;  // Total operations needed  int total = minDeletions + minInsertions;  return total; } int main() {    string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  cout << res;  return 0; } 
Java
// Java program to find the minimum of insertion and // deletion using tabulation. class GfG {    static int lcs(String s1 String s2) {    int m = s1.length();  int n = s2.length();  // Initializing a matrix of size (m+1)*(n+1)  int[][] dp = new int[m + 1][n + 1];  // Building dp[m+1][n+1] in bottom-up fashion  for (int i = 1; i <= m; ++i) {  for (int j = 1; j <= n; ++j) {  if (s1.charAt(i - 1) == s2.charAt(j - 1))  dp[i][j] = dp[i - 1][j - 1] + 1;  else  dp[i][j] = Math.max(dp[i - 1][j]  dp[i][j - 1]);  }  }  // dp[m][n] contains length of LCS for s1[0..m-1]  // and s2[0..n-1]  return dp[m][n];  }  static int minOperations(String s1 String s2) {    int m = s1.length();  int n = s2.length();  // the length of the LCS for s1[0..m-1] and  // str2[0..n-1]  int len = lcs(s1 s2);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s1  int minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions;  }  public static void main(String[] args) {    String s1 = 'AGGTAB';  String s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  System.out.println(res);  } } 
Python
# Python program to find the minimum of insertion and deletion # using tabulation. def lcs(s1 s2): m = len(s1) n = len(s2) # Initializing a matrix of size (m+1)*(n+1) dp = [[0] * (n + 1) for _ in range(m + 1)] # Building dp[m+1][n+1] in bottom-up fashion for i in range(1 m + 1): for j in range(1 n + 1): if s1[i - 1] == s2[j - 1]: dp[i][j] = dp[i - 1][j - 1] + 1 else: dp[i][j] = max(dp[i - 1][j] dp[i][j - 1]) # dp[m][n] contains length of LCS for # s1[0..m-1] and s2[0..n-1] return dp[m][n] def minOperations(s1 s2): m = len(s1) n = len(s2) # the length of the LCS for  # s1[0..m-1] and s2[0..n-1] lengthLcs = lcs(s1 s2) # Characters to delete from s1 minDeletions = m - lengthLcs # Characters to insert into s1 minInsertions = n - lengthLcs # Total operations needed return minDeletions + minInsertions s1 = 'AGGTAB' s2 = 'GXTXAYB' res = minOperations(s1 s2) print(res) 
C#
// C# program to find the minimum of insertion and deletion // using tabulation. using System; class GfG {    static int Lcs(string s1 string s2) {    int m = s1.Length;  int n = s2.Length;  // Initializing a matrix of size (m+1)*(n+1)  int[ ] dp = new int[m + 1 n + 1];  // Building dp[m+1][n+1] in bottom-up fashion  for (int i = 1; i <= m; ++i) {  for (int j = 1; j <= n; ++j) {  if (s1[i - 1] == s2[j - 1])  dp[i j] = dp[i - 1 j - 1] + 1;  else  dp[i j] = Math.Max(dp[i - 1 j]  dp[i j - 1]);  }  }  // dp[m n] contains length of LCS for s1[0..m-1]  // and s2[0..n-1]  return dp[m n];  }  static int minOperations(string s1 string s2) {    int m = s1.Length;  int n = s2.Length;  // the length of the LCS for s1[0..m-1] and  // s2[0..n-1]  int len = Lcs(s1 s2);  // Characters to delete from str1  int minDeletions = m - len;  // Characters to insert into str1  int minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions;  }  static void Main() {    string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  Console.WriteLine(res);  } } 
JavaScript
// JavaScript program to find the minimum of insertion and // deletion using tabulation. function lcs(s1 s2) {  let m = s1.length;  let n = s2.length;  // Initializing a matrix of size (m+1)*(n+1)  let dp = Array(m + 1).fill().map(  () => Array(n + 1).fill(0));  // Building dp[m+1][n+1] in bottom-up fashion  for (let i = 1; i <= m; ++i) {  for (let j = 1; j <= n; ++j) {  if (s1[i - 1] === s2[j - 1])  dp[i][j] = dp[i - 1][j - 1] + 1;  else  dp[i][j]  = Math.max(dp[i - 1][j] dp[i][j - 1]);  }  }  // dp[m][n] contains length of LCS for s1[0..m-1] and  // s2[0..n-1]  return dp[m][n]; } function minOperations(s1 s2) {  let m = s1.length;  let n = s2.length;  // the length of the LCS for s1[0..m-1] and s2[0..n-1]  let len = lcs(s1 s2);  // Characters to delete from s1  let minDeletions = m - len;  // Characters to insert into s1  let minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions; } let s1 = 'AGGTAB'; let s2 = 'GXTXAYB'; let res = minOperations(s1 s2); console.log(res); 

Ieșire
5

Utilizarea DP de jos în sus (optimizarea spațiului) – O(n^2) timp și O(n) spațiu

În abordarea anterioară, cea mai lungă secvență comună (LCS) utilizări de algoritm O(n * n) spațiu pentru depozitarea întregului tabelul dp . Cu toate acestea, deoarece fiecare valoare în dp[i][j ] depinde doar de rândul curent iar cel rândul anterior nu trebuie să depozităm întreaga masă. Acest lucru poate fi optimizat prin stocarea numai a rândurilor curente și anterioare. Pentru mai multe detalii consultați O soluție optimizată pentru spațiu a LCS .

C++
// C++ program to find the minimum of insertion and deletion // using space optimized. #include    using namespace std; int lcs(string &s1 string &s2) {    int m = s1.length() n = s2.length();  vector<vector<int>> dp(2 vector<int>(n + 1));  for (int i = 0; i <= m; i++) {  // Compute current binary index. If i is even  // then curr = 0 else 1  bool curr = i & 1;  for (int j = 0; j <= n; j++) {    // Initialize first row and first column with 0  if (i == 0 || j == 0)  dp[curr][j] = 0;  else if (s1[i - 1] == s2[j - 1])  dp[curr][j] = dp[1 - curr][j - 1] + 1;  else  dp[curr][j] = max(dp[1 - curr][j] dp[curr][j - 1]);  }  }  return dp[m & 1][n]; } int minOperations(string s1 string s2) {  int m = s1.size();  int n = s2.size();  // the length of the LCS for s1[0..m-1] and s2[0..n-1]  int len = lcs(s1 s2);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s1  int minInsertions = n - len;  // Total operations needed  int total = minDeletions + minInsertions;  return total; } int main() {  string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  cout << res;  return 0; } 
Java
// Java program to find the minimum of insertion and // deletion using space optimized. class GfG {    static int lcs(String s1 String s2) {    int m = s1.length();  int n = s2.length();  // Initializing a 2D array with size (2) x (n + 1)  int[][] dp = new int[2][n + 1];  for (int i = 0; i <= m; i++) {  // Compute current binary index. If i is even  // then curr = 0 else 1  int curr = i % 2;  for (int j = 0; j <= n; j++) {    // Initialize first row and first column  // with 0  if (i == 0 || j == 0)  dp[curr][j] = 0;  else if (s1.charAt(i - 1)  == s2.charAt(j - 1))  dp[curr][j] = dp[1 - curr][j - 1] + 1;  else  dp[curr][j] = Math.max(dp[1 - curr][j]  dp[curr][j - 1]);  }  }  return dp[m % 2][n];  }  static int minOperations(String s1 String s2) {    int m = s1.length();  int n = s2.length();  // the length of the LCS for s1[0..m-1] and  // s2[0..n-1]  int len = lcs(s1 s2);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s1  int minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions;  }  public static void main(String[] args) {    String s1 = 'AGGTAB';  String s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  System.out.println(res);  } } 
Python
# Python program to find the minimum of insertion and deletion # using space optimized. def lcs(s1 s2): m = len(s1) n = len(s2) # Initializing a matrix of size (2)*(n+1) dp = [[0] * (n + 1) for _ in range(2)] for i in range(m + 1): # Compute current binary index. If i is even # then curr = 0 else 1 curr = i % 2 for j in range(n + 1): # Initialize first row and first column with 0 if i == 0 or j == 0: dp[curr][j] = 0 # If the last characters of both substrings match elif s1[i - 1] == s2[j - 1]: dp[curr][j] = dp[1 - curr][j - 1] + 1 # If the last characters do not match # find the maximum LCS length by: # 1. Excluding the last character of s1 # 2. Excluding the last character of s2 else: dp[curr][j] = max(dp[1 - curr][j] dp[curr][j - 1]) # dp[m & 1][n] contains length of LCS for s1[0..m-1] and s2[0..n-1] return dp[m % 2][n] def minOperations(s1 s2): m = len(s1) n = len(s2) # the length of the LCS for s1[0..m-1] and s2[0..n-1] length = lcs(s1 s2) # Characters to delete from s1 minDeletions = m - length # Characters to insert into s1 minInsertions = n - length # Total operations needed return minDeletions + minInsertions s1 = 'AGGTAB' s2 = 'GXTXAYB' res = minOperations(s1 s2) print(res) 
C#
// C# program to find the minimum of insertion and deletion // using space optimized. using System; class GfG {  static int lcs(string s1 string s2) {    int m = s1.Length;  int n = s2.Length;  // Initializing a matrix of size (2)*(n+1)  int[][] dp = new int[2][];  dp[0] = new int[n + 1];  dp[1] = new int[n + 1];  for (int i = 0; i <= m; i++) {    // Compute current binary index. If i is even  // then curr = 0 else 1  int curr = i % 2;  for (int j = 0; j <= n; j++) {    // Initialize first row and first column  // with 0  if (i == 0 || j == 0)  dp[curr][j] = 0;  // If the last characters of both substrings  // match  else if (s1[i - 1] == s2[j - 1])  dp[curr][j] = dp[1 - curr][j - 1] + 1;  // If the last characters do not match  // find the maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  else  dp[curr][j] = Math.Max(dp[1 - curr][j]  dp[curr][j - 1]);  }  }  // dp[m & 1][n] contains length of LCS for  // s1[0..m-1] and s2[0..n-1]  return dp[m % 2][n];  }  static int minOperations(string s1 string s2) {    int m = s1.Length;  int n = s2.Length;  // the length of the LCS for s1[0..m-1] and  // s2[0..n-1]  int length = lcs(s1 s2);  // Characters to delete from s1  int minDeletions = m - length;  // Characters to insert into s1  int minInsertions = n - length;  // Total operations needed  return minDeletions + minInsertions;  }  static void Main(string[] args) {    string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  Console.WriteLine(res);  } } 
JavaScript
// JavaScript program to find the minimum of insertion and // deletion using space optimized. function lcs(s1 s2) {  const m = s1.length;  const n = s2.length;  // Initializing a matrix of size (2)*(n+1)  const dp  = Array(2).fill().map(() => Array(n + 1).fill(0));  for (let i = 0; i <= m; i++) {    // Compute current binary index. If i is even  // then curr = 0 else 1  const curr = i % 2;  for (let j = 0; j <= n; j++) {    // Initialize first row and first column with 0  if (i === 0 || j === 0)  dp[curr][j] = 0;  // If the last characters of both substrings  // match  else if (s1[i - 1] === s2[j - 1])  dp[curr][j] = dp[1 - curr][j - 1] + 1;  // If the last characters do not match  // find the maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  else  dp[curr][j] = Math.max(dp[1 - curr][j]  dp[curr][j - 1]);  }  }  // dp[m & 1][n] contains length of LCS for s1[0..m-1]  // and s2[0..n-1]  return dp[m % 2][n]; } function minOperations(s1 s2) {  const m = s1.length;  const n = s2.length;  // the length of the LCS for s1[0..m-1] and s2[0..n-1]  const length = lcs(s1 s2);  // Characters to delete from s1  const minDeletions = m - length;  // Characters to insert into s1  const minInsertions = n - length;  // Total operations needed  return minDeletions + minInsertions; } const s1 = 'AGGTAB'; const s2 = 'GXTXAYB'; const res = minOperations(s1 s2); console.log(res); 

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