暴力解法
/**
* @param {number[]} nums
* @return {number[]}
*/
var findDuplicates = function (nums) {
let arr = [];
let result = [];
nums.forEach((data) => {
arr.includes(data) ? result.push(data) : arr.push(data);
});
return result;
};

哈希表
/**
* @param {number[]} nums
* @return {number[]}
*/
var findDuplicates = function (nums) {
const map = new Map();
const arr = [];
for (let i = 0; i < nums.length; i++) {
if (map.has(nums[i])) {
arr.push(nums[i]);
map.delete(nums[i]);
} else {
map.set(nums[i]);
}
}
return arr;
};

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