leetcode editdistance

class Solution {
public:
    int minDistance(string word1, string word2) {
        int m=word1.size();
        int n=word2.size();
        if(m==0)return n;
        if(n==0)return m;
        int v[501][501];
        int i,j;
        for(i=0;i<=m;i++)
        {
          v[i][0]=i;
        }     
        for(j=0;j<=n;j++)
        {
            v[0][j]=j;
        }
        for(i=1;i<=m;i++)
        {
           for(j=1;j<=n;j++)
           {
               if(word1[i-1]==word2[j-1])
               v[i][j]=v[i-1][j-1];
               else v[i][j]=min(v[i][j-1],min(v[i-1][j],v[i-1][j-1]))+1;
           }         
        }
        return v[m][n];          
    }
};