leetcode 3. Longest Substring Without Repeating Characters的c语言解决

问题描述：

Given a string, find the length of the longest substring without repeating characters.
Examples:
Given

"abcabcbb"

, the answer is

"abc"

, which the length is 3.
Given

"bbbbb"

, the answer is

"b"

, with the length of 1.
Given

"pwwkew"

, the answer is

"wke"

, with the length of 3. Note that the answer must be a substring,

"pwke"

is a subsequence and not a substring.
解决思路：算出每个字符开始不重复最长字符串数，例如'pwwkew'， 从'p'开始最长不重复字符串数为2，从第一个'w'开始的为1，从第二个'w'开始的为3，这样比较下去，代码如下int lengthOfLongestSubstring(char* s) {
if(!strlen(s)) return 0;
int ans = 1, tmp = 1;
int k;
for(int i = 0; i<strlen(s); i++){
for(int j = i+1; j<strlen(s); j++){
for(k=i; k<j; k++){
//看j对应的字符在i到j之间是否重复，如有跳出第三层循环
if(s[k] == s[j])
break;
}
//不重复的情况
if(k == j)
tmp++;
//当有重复的时候，直接结束第二层循环，回到第一个循环检查下一字符
else
break;
}
ans = (ans>tmp)?ans:tmp;
tmp = 1;
}
return ans;
}