31 - Edit Distance.cpp

class Solution {
public:
    int minDistance(string word1, string word2) {
        
        vector < vector <int> > dp(word1.size()+1, vector <int> (word2.size()+1, 0));
        
        for(int i = 1; i<=word1.size(); i++){
            dp[i][0] = dp[i-1][0] + 1;
        }

        for(int i = 1; i<=word2.size(); i++){
            dp[0][i] = dp[0][i-1] + 1;
        }
        
        for(int i = 1; i<=word1.size(); i++){
            for(int j = 1; j<=word2.size(); j++){
                if(word1[i-1] != word2[j-1]){
                    dp[i][j] = min(dp[i-1][j-1], min(dp[i-1][j], dp[i][j-1])) + 1;
                }
                else{
                    dp[i][j] = dp[i-1][j-1];
                }
            }
        }
        
        return dp[word1.size()][word2.size()];
    }
};