[Leetcode] Edit Distance

Given two words word1 and word2, find the minimum number of steps required to convert word1 to word2. (each operation is counted as 1 step.)

You have the following 3 operations permitted on a word:

a) Insert a character
b) Delete a character
c) Replace a character

Solution:

http://blog.163.com/gjx_12358@126/blog/static/895363452014232191498

可以通过画一张2维的表来进行查看。

 1 public class Solution {
 2     public int minDistance(String word1, String word2) {
 3         int N1=word1.length();
 4         int N2=word2.length();
 5         int[][] dp=new int[N1+1][N2+1];
 6         for(int i=0;i<=N1;++i){
 7             dp[i][0]=i;
 8         }
 9         for(int j=0;j<=N2;++j){
10             dp[0][j]=j;
11         }
12         for(int i=1;i<=N1;++i){
13             for(int j=1;j<=N2;++j){
14                 if(word1.charAt(i-1)==word2.charAt(j-1)){
15                     dp[i][j]=dp[i-1][j-1];
16                 }else{
17                     dp[i][j]=Math.min(dp[i-1][j-1], Math.min(dp[i-1][j], dp[i][j-1]))+1;
18                 }
19             }
20         }
21         return dp[N1][N2];
22     }
23 }

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2015-02-20:

http://www.cnblogs.com/springfor/p/3896167.html