多维dp篇

class Solution {
    public int minDistance(String word1, String word2) {
          char [] s=word1.toCharArray();
          char [] t=word2.toCharArray();
          int n=s.length;
          int m=t.length;
          int [][] f=new int[n+1][m+1];
          for (int j=1;j<=m;j++){
                f[0][j]=j;
          }
          for(int i=0;i<n;i++){
            f[i+1][0]=i+1;
            for(int j=0;j<m;j++){
                f[i+1][j+1]=s[i]==t[j]?f[i][j]:Math.min(Math.min(f[i][j+1],f[i+1][j]),f[i][j])+1;
            }
          }
          return f[n][m];
    }
}