Find the K smallest numbers in an unsorted integer array A. The returned numbers should be in ascending order.
Assumptions
A is not null
K is >= 0 and smaller than or equal to size of A
Return
an array with size K containing the K smallest numbers in ascending order
Examples
A = {3, 4, 1, 2, 5}, K = 3, the 3 smallest numbers are {1, 2, 3}
1 public int[] kSmallest(int[] array, int k) {
2 // Write your solution here
3 int[] res = minHeap(array, k);
4 return res ;
5
6 }
7 //method 1: min heap
8 private int[] minHeap(int[] array, int k){
9 int[] res = new int[k] ;
10 //this is the priority queue
11 Queue<Integer> queue = new PriorityQueue<Integer>() ;
12 //step1 : offer all items in the queue
13 for (int i=0; i<array.length ; i++) {
14 queue.offer(array[i]);
15 }
16 //step 2, poll the k items out
17 for (int i=0; i<k; i++) {
18 int value = queue.poll();
19 res[i] = value;
20 }
21 return res ;
22 }
