[LeetCode]3. Longest Substring Without Repeating Characters

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.

class Solution {
public:
int lengthOfLongestSubstring(string s) {
int sizeOfS = s.size();
if(sizeOfS <= 1)
return sizeOfS;
int nowLen = 0,iOfS = 0,longestLen = 0;
string subStr;
for(int i = 0; i < sizeOfS; ++i){
auto iOfR = subStr.find(s[i]);//子串中和s[i]重复的位置
if(iOfR == string::npos){
subStr += s[i];
++ nowLen;
}
else{
nowLen = 0;
//由于循环前i还会++,所以这里i定位于重复字母在s中的下标
i = iOfS +iOfR;
iOfS = i + 1;
subStr = "";
}
if(nowLen > longestLen)
longestLen = nowLen;
}
return longestLen;
}
};