Leetcode: Longest Substring Without Repeating Characters

Longest Substring Without Repeating Characters

Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without
repeating letters for "abcabcbb" is "abc", which the length is 3. For "bbbbb" the longest substring is "b", with the length of 1.

Idea: The idea of this problem is to check the longest substring (no repeating) for each position, keep track the max length in this process. We need a int character to store the visited information of each character.

class Solution {
public:
int lengthOfLongestSubstring(string s) {
if(s.size() <= 1) return s.size();
int max_len = 0;
int i=0;
while (i<s.size()) {
int j=i;
vector<int> visited(256, 0);
while (j < s.size()) {
if(visited[s[j]] == 0){
visited[s[j]] = 1;
++j;
}
else
{
break;
}
}
max_len = max(max_len, j-i);
while(s[i] != s[j]) {
++i;
}
++i;
}
return max_len;
}
};