[python]11724接続表示個数

👉 11724接続要素数

import sys
sys.setrecursionlimit(10**6)

def dfs(graph, visited, n):
    visited[n] = 1
    for i in graph[n]:
        if visited[i] != 1:
            visited[i] = 1
            dfs(graph, visited, i)

n, m = map(int, sys.stdin.readline().split())
graph = {}
for i in range(n):
    graph[i + 1] = []
visited = [0] * (len(graph) + 1)
for i in range(m):
    u, v = map(int, sys.stdin.readline().split())
    graph[u].append(v)
    graph[v].append(u)

visited[0] = 1
cnt = 0
while 0 in visited:
    node = 0
    for i in range(len(visited)):
        if visited[i] == 0:
            node = i
            break
    if node != 0:
        dfs(graph, visited, node)
        cnt += 1
print(cnt)