Function findDuplicate

javascript/0287-find-the-duplicate-number.js:7–19

(nums)

 * @return {number}
 */
var findDuplicate = function (nums) {
    nums.sort(
        (a, b) => a - b,
    ); /* Time O(N * log(N)) | HeapSort Space O(1) | QuickSort Space O(log(N)) */

    for (let i = 1; i < nums.length; i++) {
        /* Time O(N) */
        const isPrevDuplicate = nums[i - 1] === nums[i];
        if (isPrevDuplicate) return nums[i];
    }

    return -1;
};

/**
 * https://leetcode.com/problems/find-the-duplicate-number/