class Solution {
    
    
public:
    int minDistance(string word1, string word2) {
    
    
        int m=word1.size()+1,n=word2.size()+1;
        int dp[m][n];
        for(int i=0;i<m;++i) dp[i][0]=i;
        for(int j=0;j<n;++j) dp[0][j]=j;
        for(int i=1;i<m;++i)
            for(int j=1;j<n;++j)
                if(word1[i-1]==word2[j-1])
                    dp[i][j]=dp[i-1][j-1];
                else
                    dp[i][j]=min(min(dp[i-1][j-1],dp[i][j-1]),dp[i-1][j])+1;  
        return dp[m-1][n-1];
    }

};