Given two wordsword1andword2, find the minimum number of steps required to makeword1andword2the same, where in each step you can delete one character in either string.

Example 1:

Input: "sea", "eat"

Output: 2

Explanation:
 You need one step to make "sea" to "ea" and another step to make "eat" to "ea".

Solution 1: 找longest common subsequence，单词长度减公共长度即删除个数

Solution 2: 类似edit distance, 删2个跟删一个的操作

    public int minDistance(String word1, String word2) {
        int len1 = word1.length(), len2 = word2.length();
        if (len1 == 0) return len2;
        if (len2 == 0) return len1;

        // dp[i][j] stands for distance of first i chars of word1 and first j chars of word2
        int[][] dp = new int[len1 + 1][len2 + 1];
        for (int i = 0; i <= len1; i++)
            dp[i][0] = i;
        for (int j = 0; j <= len2; j++)
            dp[0][j] = j;

        for (int i = 1; i <= len1; i++) {
            for (int j = 1; j <= len2; j++) {
                if (word1.charAt(i - 1) == word2.charAt(j - 1))
                    dp[i][j] = dp[i - 1][j - 1];
                else
                                                        各删一个
                    dp[i][j] = Math.min(Math.min(dp[i - 1][j - 1] + 2, dp[i - 1][j] + 1), dp[i][j - 1] + 1);
            }
        }

        return dp[len1][len2];
    }