Problem Link

C++ Code

class Solution {
public:
    int lengthOfLongestSubstring(string s) {

        int n = s.size();

        vector<bool> isPresent(256, false);

        int i=0, j=0;
        int maxLength = 0;

        while(j<n) {

            if(!isPresent[(int) s[j]]) {

                isPresent[(int) s[j]] = true;
                maxLength = max(maxLength, j-i+1);
                j++;

            } else {

                isPresent[(int) s[i]] = false;
                i++;

            }

        }

        return maxLength;
    }
};

TypeScript Code

function lengthOfLongestSubstring(s: string): number {

    const n: number = s.length;

    let isPresent: Array<boolean> = new Array<boolean>(256).fill(false);

    let i = 0, j = 0;
    let maxLength = 0;

    while(j<n) {

        if(!isPresent[s.charCodeAt(j)]) {

            isPresent[s.charCodeAt(j)] = true;
            maxLength = Math.max(maxLength, j-i+1);
            j++;

        } else {

            isPresent[s.charCodeAt(i)] = false;
            i++;

        }

    }

    return maxLength;
};

Go Code

func lengthOfLongestSubstring(s string) int {

    n := len(s);

    isPresent := make([]bool, 256);

    i := 0;
    j := 0;
    maxLength := 0;

    for j<n {

        if !isPresent[int (s[j])] {

            isPresent[int (s[j])] = true;

            if maxLength < j-i+1 {
                maxLength = j-i+1;
            }

            j++;

        } else {

            isPresent[int (s[i])] = false;
            i++;

        }

    }

    return maxLength;
}