647-Palindromic-Substrings.ts

function countSubstrings(s: string): number {
    let res = 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]) {
            res += 1;
            l -= 1;
            r += 1;
        }

        l = i;
        r = i + 1;

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

    return res;
}