题目
Given a m * n matrix mat of ones (representing soldiers) and zeros (representing civilians), return the indexes of the k weakest rows in the matrix ordered from the weakest to the strongest.
A row i is weaker than row j, if the number of soldiers in row i is less than the number of soldiers in row j, or they have the same number of soldiers but i is less than j. Soldiers are always stand in the frontier of a row, that is, always ones may appear first and then zeros.
解题思路
先统计出来每一行有多少个士兵，然后连同行号一起放到堆里，pop出来前k个
代码
class Solution:
def kWeakestRows(self, mat: List[List[int]], k: int) -> List[int]:
power = []
for r, row in enumerate(mat):
tmp = 0
for n in row:
if n:
tmp += 1
else:
break
power.append((tmp, r))
heapq.heapify(power)
return [heapq.heappop(power)[1] for _ in range(k)]
