373. Find K Pairs with Smallest Sums

You are given two integer arrays nums1 and nums2 sorted in ascending order and an integer k.

Define a pair (u,v) which consists of one element from the first array and one element from the second array.

Find the k pairs (u1,v1),(u2,v2) …(uk,vk) with the smallest sums.

Example 1:

Given nums1 = [1,7,11], nums2 = [2,4,6], k = 3

Return: [1,2],[1,4],[1,6]

The first 3 pairs are returned from the sequence:

[1,2],[1,4],[1,6],[7,2],[7,4],[11,2],[7,6],[11,4],[11,6]

Example 2:

Given nums1 = [1,1,2], nums2 = [1,2,3], k = 2

Return: [1,1],[1,1]

The first 2 pairs are returned from the sequence:

[1,1],[1,1],[1,2],[2,1],[1,2],[2,2],[1,3],[1,3],[2,3]

Example 3:

Given nums1 = [1,2], nums2 = [3], k = 3

Return: [1,3],[2,3]

All possible pairs are returned from the sequence:

[1,3],[2,3]

留坑，后面补充其他解法

public class Solution {
public List<int[]> kSmallestPairs(int[] nums1, int[] nums2, int k) {
List<int[]> res = new ArrayList<int[]>();
PriorityQueue<int[]> queue = new PriorityQueue<>(k, new Comparator<int[]>(){
@Override
public int compare(int[] o1, int[] o2){
return o1[0] + o1[1] - o2[0] - o2[1];
}
});
for (int i = 0; i < nums1.length; i++) {
for (int j = 0; j < nums2.length; j++) {
queue.add(new int[]{nums1[i], nums2[j]});
}
}
while (k-- > 0) {
int[] tmp = queue.poll();
if(tmp == null) break;
res.add(tmp);
}
return res;
}
}