#3.Longest Substring Without Repeating Characters [LeetCode Grind 75 in Java]

class Solution {
    public int lengthOfLongestSubstring(String s) {
        HashMap<Character , Integer> map = new HashMap<>();
        int l = 0;
        int ans = 0;

        int n = s.length();
        for(int r = 0 ; r < n ; r ++){
            char c = s.charAt(r);

            if(!map.containsKey(c) || map.get(c) < l){
                map.put(c , r);
                ans = Math.max(ans, r - l + 1);
            }else{
                l = map.get(c) + 1;
                map.put(c , r);
            }
        }
        return ans;

    }
}