leetcode:378. 有序矩阵中第 K 小的元素

import heapqdef kthSmallest(matrix, k):heap = []n = len(matrix)for i in range(n):  # 使用第一列数据构建小顶堆heapq.heappush(heap, (matrix[i][0], i, 0))# 弹出k-1次k1 = 1while k1 < k:num, i, j = heapq.heappop(heap)if j < n - 1:  # 把第i行的所有数据加入小顶堆heapq.heappush(heap, (matrix[i][j + 1], i, j + 1))k1 += 1# 弹出第k次，也就得到第k小的数ans, _, _ = heapq.heappop(heap)return ansmatrix = [[1, 5, 9], [10, 11, 13], [12, 13, 15]]
k = 8
ans = kthSmallest(matrix, k)
print(ans) # 13