12345678910111213141516
export default function arrayNesting(nums: number[]): number {    let ans = 0;    const n = nums.length;    const vis: boolean[] = new Array(n).fill(0);    for (let i = 0; i < n; ++i) {        let cnt = 0;        while (!vis[i]) {            vis[i] = true;            i = nums[i];            ++cnt;        }        ans = Math.max(ans, cnt);    }    return ans;}