题解 | #编辑距离(一)#

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
        if (str1 == null || str2 == null) {
            return 0;
        }
        char[] arr1 = str1.toCharArray();
        char[] arr2 = str2.toCharArray();
        int n = arr1.length;
        int m = arr2.length;
        int[][] dp = new int[n + 1][m + 1];
        for (int i = 1; i <= n; i++) {
            dp[i][0] = dp[i - 1][0] + 1;
        }
        for (int j = 1; j <= m; j++) {
            dp[0][j] = dp[0][j - 1] + 1;
        }
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= m; j++) {
                if (arr1[i - 1] == arr2[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[n][m];
    }
}