Longest Substring without Repeating Characters

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
        int last[256];
        fill(begin(last), end(last), -1);
        int left = 0, best = 0;
        for (int right = 0; right < (int)s.size(); ++right) {
            if (last[(unsigned char)s[right]] >= left) {
                left = last[(unsigned char)s[right]] + 1;
            }
            last[(unsigned char)s[right]] = right;
            best = max(best, right - left + 1);
        }
        return best;
    }
};

func lengthOfLongestSubstring(s string) int {
    var last [256]int
    for i := range last {
        last[i] = -1
    }
    left, best := 0, 0
    for right := 0; right < len(s); right++ {
        c := s[right]
        if last[c] >= left {
            left = last[c] + 1
        }
        last[c] = right
        if right-left+1 > best {
            best = right - left + 1
        }
    }
    return best
}

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        last = [-1] * 256
        left = 0
        best = 0
        for right, ch in enumerate(s):
            c = ord(ch)
            if last[c] >= left:
                left = last[c] + 1
            last[c] = right
            if right - left + 1 > best:
                best = right - left + 1
        return best

function lengthOfLongestSubstring(s) {
    const last = new Array(256).fill(-1);
    let left = 0, best = 0;
    for (let right = 0; right < s.length; right++) {
        const c = s.charCodeAt(right);
        if (last[c] >= left) left = last[c] + 1;
        last[c] = right;
        if (right - left + 1 > best) best = right - left + 1;
    }
    return best;
}

class Solution {
    public int lengthOfLongestSubstring(String s) {
        int[] last = new int[256];
        Arrays.fill(last, -1);
        int left = 0, best = 0;
        for (int right = 0; right < s.length(); right++) {
            int c = s.charAt(right);
            if (last[c] >= left) left = last[c] + 1;
            last[c] = right;
            if (right - left + 1 > best) best = right - left + 1;
        }
        return best;
    }
}

function lengthOfLongestSubstring(s: string): number {
    const last: number[] = new Array(256).fill(-1);
    let left = 0, best = 0;
    for (let right = 0; right < s.length; right++) {
        const c = s.charCodeAt(right);
        if (last[c] >= left) left = last[c] + 1;
        last[c] = right;
        if (right - left + 1 > best) best = right - left + 1;
    }
    return best;
}