题目：原题链接（中等）
标签：数组、深度优先搜索
| 解法 | 时间复杂度 | 空间复杂度 | 执行用时 |
|---|---|---|---|
| Ans 1 (Python) | O ( N × M ) O(N×M) O(N×M) | O ( N × M ) O(N×M) O(N×M) | 548ms (55.10%) |
| Ans 2 (Python) | |||
| Ans 3 (Python) |
解法一：
class Solution:
def findBlackPixel(self, picture: List[List[str]], N: int) -> int:
dic_row = collections.defaultdict(list)
count_row = []
for i in range(len(picture)):
row = picture[i]
count_row.append(row.count("B"))
if count_row[-1] == N:
dic_row[tuple(row)].append(i)
rows = list(dic_row.values())
row_dic = {}
for r, lst in enumerate(rows):
for i in lst:
row_dic[i] = r
# print(count_row)
# print(row_dic)
ans = 0
for j in range(len(picture[0])):
count = 0
row_lst = []
for i in range(len(picture)):
if picture[i][j] == "B":
count += 1
row_lst.append(i)
if count == N:
row_set = set()
fail = False
for r in row_lst:
if r not in row_dic:
fail = True
break
row_set.add(row_dic[r])
if not fail and len(row_set) == 1:
ans += count
return ans
