알고리즘: 백준 2606번 바이러스 (feat.python)

 

2606번: 바이러스

 

 

import sys
read = sys.stdin.readline


def bfs(start, dic):
    queue = [start]
    while(queue):
        pop = queue.pop(0)
        for i in dic[pop]:
            if i not in visited:
                visited.append(i)
                queue.append(i)
def dfs(start, dic):
    for i in dic[start]:
        if i not in visited:
            visited.append(i)
            dfs(i, dic)

def dfs2(start, dic):
    stack = [start]
    while stack:
        for i in dic[stack.pop()]:
            if i not in visited:
                visited.append(i)
                stack.append(i)





visited = [1]
dic = {}
for i in range(int(read())):
    dic[i + 1] = set()
for i in range(int(read())):
    x1, x2 = list(map(int, read().split()))
    dic[x1].add(x2)
    dic[x2].add(x1)

# bfs(1, dic)
# dfs(1, dic)
dfs2(1, dic)
# print(visited)
print(len(visited) - 1)