leetcode 521. Longest Uncommon Subsequence I 最初非公共子序列 + 直接比较即可

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.

Example 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.

这道题很简单，不要想得太复杂，两个字符串的情况很少，如果两个字符串相等，那么一定没有非共同子序列，反之，如果两个字符串不等，那么较长的那个字符串就是最长非共同子序列

建议和这一道题一起学习leetcode 522. Longest Uncommon Subsequence II 最长非公共子序列

代码如下：

#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <string>
#include <climits>
#include <algorithm>
#include <sstream>
#include <functional>
#include <bitset>
#include <numeric>
#include <cmath>

using namespace std;

class Solution
{
public:
int findLUSlength(string a, string b)
{
if (a == b)
return -1;
else
return max(a.length(),b.length());
}
};