简单动态规划

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param str1 string字符串 
     * @param str2 string字符串 
     * @return int整型
     */
    public int editDistance (String str1, String str2) {
        // write code here
        // 动态规划
        int n = str1.length();
        int m = str2.length();
        int[][] dp = new int[n + 1][m + 1];
        for (int i = 0; i <= n; i ++ ) dp[i][0] = i;
        for (int i = 0; i <= m; i ++ ) dp[0][i] = i;
        
        for (int i = 1; i <= n; i ++ ) {
            for (int j = 1; j <= m; j ++ ) {
                if (str1.charAt(i - 1) == str2.charAt(j - 1)) {
                    dp[i][j] = dp[i - 1][j - 1];
                } else {
                    dp[i][j] = Math.min(Math.min(dp[i - 1][j], dp[i][j - 1]), dp[i - 1][j - 1]) + 1;
                }
            }
        }
        return dp[n][m];
    }
}