Description
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.
题目分析
本题要求给出两个字符串的最长不相同序列。若两个字符串的长度和内容完全相同，则返回-1。
本题可以通过字符串比较函数strcmp来解决，若两个字符串相等，返回-1.若不相等，则较长的一个必定与较短的完全不相同，即较长的为最大不相同序列，返回其长度即可。
C语言代码
int findLUSlength(char* a, char* b) {
int len1=strlen(a);
int len2=strlen(b);
int lenmin=len1,lenmax=len2;
int s=strcmp(a,b);
if(s==0) //strcmp==0表示内容和长度均相同。
return -1;
else //不相同，则最长的串必定不是最短的串的子序列，因此必定是最长不同序列。
{
if(lenmax<lenmin)
lenmax=lenmin;
return lenmax;
}
}
参考文献
[1] https://leetcode.com/problems/longest-uncommon-subsequence-i/#/description
[2] http://www.bubuko.com/infodetail-2009549.html
