백준 / 실버 2 / 11754 연결 노드의 개수 / Python [그래프, Union Find, DFS]

https://www.acmicpc.net/problem/11724

그래프 문제 템플릿

# 양방향 그래프 가변 배열로
graph = [[] for _ in range(N+1)]

for _ in range(M):
	graph[a].append(b)
    graph[b].append(a)

# dfs
def dfs(start, visited):
	visited[start] = True

# 캐시 사용
visited = [False] * (N+1)
for start in range(1, N):
	if not visited[start]:
    	dfs(start, visited) ..

몰라서 참고했음

import sys
input = sys.stdin.readline
sys.setrecursionlimit(10**6)

def dfs(start, visited):
    visited[start] = True
    for end in graph[start]:
        if not visited[end]:
            dfs(end, visited)

N, M = map(int, input().split())
graph = [[] for _ in range(N+1)]

for _ in range(M):
    u, v = map(int, input().split())
    graph[u].append(v)
    graph[v].append(u)
    
visited = [False] * (N+1)
cnt = 0

for node in range(1, N+1):
    if not visited[node]:
        dfs(node, visited)
        cnt += 1
        
print(cnt)```