LeetCode-72-编辑距离

输入：word1 = "horse", word2 = "ros"
输出：3
解释：
horse -> rorse (将 'h' 替换为 'r')
rorse -> rose (删除 'r')
rose -> ros (删除 'e')

输入：word1 = "intention", word2 = "execution"
输出：5
解释：
intention -> inention (删除 't')
inention -> enention (将 'i' 替换为 'e')
enention -> exention (将 'n' 替换为 'x')
exention -> exection (将 'n' 替换为 'c')
exection -> execution (插入 'u')

public int minDistance(String word1, String word2) {
        int n1 = word1.length();
        int n2 = word2.length();
        int[][] dp = new int[n1 + 1][n2 + 1];
        // 边界状态初始化
        for (int i = 0; i < n1 + 1; i++) {
            dp[i][0] = i;
        }
        for (int j = 0; j < n2 + 1; j++) {
            dp[0][j] = j;
        }
        for (int i = 1; i < n1 + 1; i++) {
            for (int j = 1; j < n2 + 1; j++) {
                if (word1.charAt(i - 1) == word2.charAt(j - 1)) {
                    dp[i][j] = dp[i - 1][j - 1];
                } else {
                    dp[i][j] = 1 + Math.min(Math.min(dp[i - 1][j - 1], dp[i][j - 1]), dp[i - 1][j]);
                }
            }
        }
        return dp[n1][n2];
    }