1439. Find the Kth Smallest Sum of a Matrix With Sorted Rows (Hard) - TengnanYao/daily_leetcode GitHub Wiki

class Solution(object):
    def kthSmallest(self, mat, k):
        """
        :type mat: List[List[int]]
        :type k: int
        :rtype: int
        """
        result = [0]
        for row in mat:
            result = [x + y for x in result for y in row]
            result.sort()
            result = result[ : k]
        return result[-1]