"Longest Substring Without Repeating Characters"

Problem

Given a string, find the length of the longest substring without repeating characters.
Input: "abcabcbb"
Output: 3 
Explanation: The answer is "abc", with the length of 3.

Solution

This solution is in C++. Our A.I. can create solutions in multiple languages.

kayakane

#include <iostream>
#include <string>
#include <unordered_map>

using namespace std;

int lengthOfLongestSubstring(string s) {
    unordered_map<char, int> map;
    int maxLen = 0;
    int curLen = 0;
    int start = 0;
    for (int i = 0; i < s.length(); i++) {
        if (map.find(s[i]) == map.end()) {
            map[s[i]] = i;
            curLen++;
        } else {
            if (map[s[i]] >= start) {
                start = map[s[i]] + 1;
                curLen = i - map[s[i]];
            } else {
                curLen++;
            }
            map[s[i]] = i;
        }
        maxLen = max(maxLen, curLen);
    }
    return maxLen;
}

int main() {
    string s = "abcabcbb";
    cout << lengthOfLongestSubstring (s) << endl;
    return 0;
}