LeetCode 442.数组中重复的数据 - JavaScript

// ac地址：https://leetcode-cn.com/problems/find-all-duplicates-in-an-array/
// 原文地址：https://xxoo521.com/2020-02-14-find-all-duplicates-in-an-array/
/**
 * @param {number[]} nums
 * @return {number[]}
 */
var findDuplicates = function(nums) {
    const res = [];
    for (const num of nums) {
        const absNum = Math.abs(num);
        if (nums[absNum - 1] < 0) {
            res.push(absNum);
        } else {
            nums[absNum - 1] = -1 * nums[absNum - 1];
        }
    }

    return res;
};