C#LeetCode刷题之#521-最长特殊序列 Ⅰ（Longest Uncommon Subsequence I）

版权声明：Iori 的技术分享，所有内容均为本人原创，引用请注明出处，谢谢合作！ https://blog.csdn.net/qq_31116753/article/details/83046439

问题

给定两个字符串，你需要从这两个字符串中找出最长的特殊序列。最长特殊序列定义如下：该序列为某字符串独有的最长子序列（即不能是其他字符串的子序列）。

子序列可以通过删去字符串中的某些字符实现，但不能改变剩余字符的相对顺序。空序列为所有字符串的子序列，任何字符串为其自身的子序列。

输入为两个字符串，输出最长特殊序列的长度。如果不存在，则返回 -1。

输入: "aba", "cdc"

输出: 3

解析: 最长特殊序列可为 "aba" (或 "cdc")

说明:

两个字符串长度均小于100。
字符串中的字符仅含有 'a'~'z'。

---

Given a group of two strings, you need to find the longest uncommon subsequence of this group of two strings. The longest uncommon subsequence is defined as the longest subsequence of one of these strings and this subsequence should not be any subsequence of the other strings.

A subsequence is a sequence that can be derived from one sequence by deleting some characters without changing the order of the remaining elements. Trivially, any string is a subsequence of itself and an empty string is a subsequence of any string.

The input will be two strings, and the output needs to be the length of the longest uncommon subsequence. If the longest uncommon subsequence doesn't exist, return -1.

Input: "aba", "cdc"

Output: 3

Explanation: The longest uncommon subsequence is "aba" (or "cdc"), because "aba" is a subsequence of "aba", but not a subsequence of any other strings in the group of two strings. 

Note:

Both strings' lengths will not exceed 100.
Only letters from a ~ z will appear in input strings.

---

示例

public class Program {

    public static void Main(string[] args) {
        var a = "Iori's Blog";
        var b = "aba";

        var res = FindLUSlength(a, b);
        Console.WriteLine(res);

        Console.ReadKey();
    }

    private static int FindLUSlength(string a, string b) {
        //真不知道这道题存在的意思是什么
        if(a == b) return -1;
        return Math.Max(a.Length, b.Length);
    }

}

以上给出1种算法实现，以下是这个案例的输出结果：

11

---

分析：

显而易见，以上算法的时间复杂度为  。