[LeetCode]373. Find K Pairs with Smallest Sums

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https://leetcode.com/problems/find-k-pairs-with-smallest-sums/?tab=Description

给两个升序数组，找到和最小的k个pair

建一个堆，和最小的k个对最多在nums1中包含前k个元素，先把nums1的0 ~ k - 1和nums2的0配对的加到堆里面然后再poll，把poll出来的nums2的后一位和nums1的当前位加到堆里面

public class Solution {    public List<int[]> kSmallestPairs(int[] nums1, int[] nums2, int k) {        PriorityQueue<Tuple> queue = new PriorityQueue<Tuple>(new Comparator<Tuple>() {            public int compare(Tuple t1, Tuple t2) {                return t1.val - t2.val;            }        });        List<int[]> res = new LinkedList();        if (nums1.length == 0 || nums2.length == 0 || k == 0) {            return res;        }        for (int i = 0; i < nums1.length && i < k; i++) {            queue.add(new Tuple(i, 0, nums1[i] + nums2[0]));        }        while (k-- > 0 && !queue.isEmpty()) {            Tuple t = queue.poll();            res.add(new int[]{nums1[t.x], nums2[t.y]});            if (t.y == nums2.length - 1) {                continue;            }            queue.offer(new Tuple(t.x, t.y + 1, nums1[t.x] + nums2[t.y + 1]));        }        return res;    }    class Tuple {        int x;        int y;        int val;        public Tuple(int x, int y, int val) {            this.x = x;            this.y = y;            this.val = val;        }    }}

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