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0373.Find_K_Pairs_with_Smallest_Sums.py
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55 lines (40 loc) Β· 1.72 KB
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"""
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.
Return the k pairs (u1, v1), (u2, v2), ..., (uk, vk) with the smallest sums.
Example 1:
Input: nums1 = [1,7,11], nums2 = [2,4,6], k = 3
Output: [[1,2],[1,4],[1,6]]
Explanation: 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:
Input: nums1 = [1,1,2], nums2 = [1,2,3], k = 2
Output: [[1,1],[1,1]]
Explanation: 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:
Input: nums1 = [1,2], nums2 = [3], k = 3
Output: [[1,3],[2,3]]
Explanation: All possible pairs are returned from the sequence: [1,3],[2,3]
Constraints:
1 <= nums1.length, nums2.length <= 105
-109 <= nums1[i], nums2[i] <= 109
nums1 and nums2 both are sorted in ascending order.
1 <= k <= 104
"""
class Solution:
def kSmallestPairs(self, nums1: List[int], nums2: List[int], k: int) -> List[List[int]]:
hq = []
heappush(hq, (nums1[0] + nums2[0], 0, 0))
visited = set()
visited.add((0, 0))
res = []
m, n = len(nums1), len(nums2)
for _ in range(min(m*n, k)):
curr, i, j = heappop(hq)
res.append([nums1[i], nums2[j]])
if i + 1 < m and (i + 1, j) not in visited:
heappush(hq, (nums1[i + 1] + nums2[j], i + 1, j))
visited.add((i + 1, j))
if j + 1 < n and (i, j + 1) not in visited:
heappush(hq, (nums1[i] + nums2[j + 1], i, j + 1))
visited.add((i, j + 1))
return res