Minimum number of deletions and insertions

shriyanshi24jindal

Mar 28th, 2026

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Java 8.75 KB | None | 0 0

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// User function Template for Java
class Solution {
/**
* Find the LCS of both strings
* Once LCS length is found, we can remove the length of LCS from both the strings
* and then we can sum up the remaining length of both strings
*/
public int minOperations(String s1, String s2) {
int n = s1.length();
int m = s2.length();
// step-1 create a matrix of LCS
int[][] t = new int[n+1][m+1];
// step-2 initialise the matrix
for(int i=0; i<n+1; i++)
{
for(int j=0; j<m+1; j++)
{
// when string is empty, no LCS found
if(i == 0 || j == 0)
t[i][j] = 0;
}
}
// step-3 LCS iterative code
for(int i=1; i<n+1; i++)
{
for(int j=1; j<m+1; j++)
{
if(s1.charAt(i-1) == s2.charAt(j-1))
t[i][j] = 1 + t[i-1][j-1];
else
t[i][j] = Math.max(t[i-1][j], t[i][j-1]);
}
}
int lcsLength = t[n][m];
int deletion = n-lcsLength;
int insertion = m-lcsLength;
return deletion+insertion;
}
}

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// User function Template for Java

class Solution {
    /**
     * Find the LCS of both strings
     * Once LCS length is found, we can remove the length of LCS from both the strings
     * and then we can sum up the remaining length of both strings
     */
    public int minOperations(String s1, String s2) {
        int n = s1.length();
        int m = s2.length();
        
        // step-1 create a matrix of LCS
        int[][] t = new int[n+1][m+1];
        
        // step-2 initialise the matrix
        for(int i=0; i<n+1; i++)
        {
            for(int j=0; j<m+1; j++)
            {
                // when string is empty, no LCS found
                if(i == 0 || j == 0)
                    t[i][j] = 0;
            }
        }
        
        // step-3 LCS iterative code
        for(int i=1; i<n+1; i++)
        {
            for(int j=1; j<m+1; j++)
            {
                if(s1.charAt(i-1) == s2.charAt(j-1))
                    t[i][j] = 1 + t[i-1][j-1];
                
                else
                    t[i][j] = Math.max(t[i-1][j], t[i][j-1]);
            }
        }
        
        int lcsLength = t[n][m];
        
        int deletion = n-lcsLength;
        int insertion = m-lcsLength;
        
        return deletion+insertion;
    }
}