0005-longest-palindromic-substring.ts

function longestPalindrome(s: string): string {
    let res = '';
    let resLen = 0;

    for (let i = 0; i < s.length; i++) {
        let l = i;
        let r = i;

        while (l >= 0 && r < s.length && s[l] === s[r]) {
            if (r - l + 1 > resLen) {
                res = s.slice(l, r + 1);
                resLen = r - l + 1;
            }

            l -= 1;
            r += 1;
        }

        l = i;
        r = i + 1;

        while (l >= 0 && r < s.length && s[l] === s[r]) {
            if (r - l + 1 > resLen) {
                res = s.slice(l, r + 1);
                resLen = r - l + 1;
            }

            l -= 1;
            r += 1;
        }
    }

    return res;
}