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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
# @param {Integer[]} nums
# @param {Integer} k
# @return {Integer[]}
def top_k_frequent(nums, k)
numhash = Hash.new(0)
nums.each {|num| numhash[num] += 1}
newhash = numhash.sort_by {|k, v| -v}
ret_array = []
for i in 0...k
ret_array << newhash[i][0]
end
return ret_array
end