TopKFrequentElements347.kt

package 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
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.
 */
fun topKFrequent(nums: IntArray, k: Int): IntArray {
    val map=HashMap<Int,Int>()
    nums.forEach{num->
        map[num]=(map[num]?:0)+1
    }

    var i=0
    val result=IntArray(k)
    while(i<k)
    {
        var maxValue=0
        var maxKey=0
        map.forEach{pair->
            if(pair.value>maxValue)
            {
                maxValue=pair.value
                maxKey=pair.key
            }
        }
        result[i]=maxKey
        map.remove(maxKey)
        i++
    }
    return result
}