[leetcode]Edit Distance

class Solution {
public:
    int minDistance(string word1, string word2) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        
        int M = word1.size();
        int N = word2.size();
        
        if(M == 0) return N;
        if(N == 0) return M;
        
        vector<vector<int>> f(M+1, vector<int>(N+1, 0));
        for(int i = 0; i <= M; i++){
            f[i][0] = i;
        }
        for(int j = 0; j <= N; j++){
            f[0][j] = j;
        }
        
        for(int i = 1; i <= M; i++){
            for(int j = 1; j <= N; j++){
                if(word1[i-1] == word2[j-1]){
                    f[i][j] = min(f[i-1][j]+1, f[i][j-1]+1);
                    f[i][j] = min(f[i][j],f[i-1][j-1]);
                }else{
                    f[i][j] = min(f[i-1][j]+1, f[i][j-1]+1);
                    f[i][j] = min(f[i][j],f[i-1][j-1]+1);
                }
            }
        }
        return f[M][N];
        
    }
};