题目
There are n cities. Some of them are connected, while some are not. If city a is connected directly with city b, and city b is connected directly with city c, then city a is connected indirectly with city c.
A province is a group of directly or indirectly connected cities and no other cities outside of the group.
You are given an n x n matrix isConnected where isConnected[i][j] = 1 if the ith city and the jth city are directly connected, and isConnected[i][j] = 0 otherwise.
Return the total number of provinces.
解题思路
题目相当于求无向图连通分量个数
代码
class Solution:
def findCircleNum(self, isConnected: List[List[int]]) -> int:
n = len(isConnected)
res = 0
visit = set()
for i in range(n):
if i in visit:
continue
s = [i]
visit.add(i)
res += 1
while s:
cur = s.pop()
for j in range(n):
if j not in visit and isConnected[cur][j] == 1:
s.append(j)
visit.add(j)
return res
