LeetCode-in-All

347. Top K Frequent Elements

Medium

Given an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order.

Example 1:

Input: nums = [1,1,1,2,2,3], k = 2

Output: [1,2]

Example 2:

Input: nums = [1], k = 1

Output: [1]

Constraints:

• 1 <= nums.length <= 105
• -104 <= nums[i] <= 104
• k is in the range [1, the number of unique elements in the array].
• It is guaranteed that the answer is unique.

Follow up: Your algorithm’s time complexity must be better than O(n log n), where n is the array’s size.

Solution

/**
 * @param {number[]} nums
 * @param {number} k
 * @return {number[]}
 */
var topKFrequent = function (nums, k) {
    let obj = {}, result = []
    for (let item of nums) {
        obj[item] = (obj[item] ? obj[item] : 0) + 1
    }
    let temp = Object.entries(obj).sort((a, b) => b[1] - a[1])
    for (let i = 0; i < k; i++) {
        result.push(Number(temp[i][0]))
    }
    return result
};

export { topKFrequent }

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