[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。

public class Solution {
    public int minDistance(String word1, String word2) {
        int N1=word1.length();
        int N2=word2.length();
        int[][] dp=new int[N1+1][N2+1];
        for(int i=0;i<=N1;++i){
            dp[i][0]=i;
        }
        for(int j=0;j<=N2;++j){
            dp[0][j]=j;
        }
        for(int i=1;i<=N1;++i){
            for(int j=1;j<=N2;++j){
                if(word1.charAt(i-1)==word2.charAt(j-1)){
                    dp[i][j]=dp[i-1][j-1];
                }else{
                    dp[i][j]=Math.min(dp[i-1][j-1], Math.min(dp[i-1][j], dp[i][j-1]))+1;
                }
            }
        }
        return dp[N1][N2];
    }
}

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2015-02-20:

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