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 <= 105kis 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
class Solution {
/**
* @param Integer[] $nums
* @param Integer $k
* @return Integer[]
*/
public function topKFrequent($nums, $k) {
$count = [];
foreach ($nums as $num) {
if (!isset($count[$num])) {
$count[$num] = 0;
}
$count[$num] += 1;
}
arsort($count);
$result = [];
$r = 0;
foreach ($count as $i => $num) {
$result[] = $i;
$r++;
if ($r === $k) {
break;
}
}
return $result;
}
}