# 521.Longest Uncommon Subsequence I

**521.Longest Uncommon Subsequence I**

难度:Easy

> 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。

```
示例 :

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'。
```

脑筋急转弯？没看出这题的意义。。。代码如下：

```
class Solution {
public:
    int findLUSlength(string a, string b) {
        int flag=1;
        if(b.length()<a.length()) swap(a,b);
        if(b.length()==0)
            return -1;
        if(a.length()==b.length())
            if(a==b) flag=0;

        return flag? b.length(): -1;
        
    }
};
```


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