bright

programmers.co.kr/learn/courses/30/lessons/43162

def dfs(graph, v, visited) : 
    tmp = 0 
    if not visited[v] :
        visited[v] = True
        for i in range( len(graph[v]) ):
            if graph[v][i] :
                dfs(graph, i, visited)
                tmp += 1 
        
        if tmp >= 1 : return True
    return False

def solution(n, computers):

    visited = [False] * n
    answer = 0

    for i in range(n):
        if dfs(computers, i , visited): 
            answer += 1 
    return answer

=> 조금 더 간결하게 

def dfs(graph,v, visited):
    
    if visited[v] == 1 : 
        return False 
    
    visited[v]=1
    for i in range(len(graph[v])):
        if graph[v][i]==1 :
          dfs(graph,i,visited)
    return True
    

def solution(n, computers):
    
    answer = 0 
    visited= [0]*n
    
    for i in range(n):
        if dfs(computers,i,visited) == True : 
            answer += 1 

    return answer

programmers.co.kr/learn/courses/30/lessons/43165

def solution(numbers, target):
    sup= [0]
    for i in numbers:
        sub = []
        for j in sup : 
            sub.append(j+i)
            sub.append(j-i)
        sup = sub
    return sup.count(target)

programmers.co.kr/learn/courses/30/lessons/64061

def solution(board, moves):
    
    doll = [0] # 쌓이는 인형 
    answer = 0

    for m in moves:
        for i in range(len(board)):
            if board[i][m-1] != 0 :

                if board[i][m-1] == doll[-1]:
                    answer += 2 
                    doll.pop()
                else: 
                    doll.append(board[i][m-1])
                board[i][m-1] = 0 
                break
        
    return answer

www.acmicpc.net/problem/9465

def sticker(n,data):

  data[0][1] += data[1][0] 
  data[1][1] += data[0][0] 

  for j in range(2,n):
    data[0][j] += max( data[1][j-2],  data[1][j-1] )
    data[1][j] += max ( data[0][j-2], data[0][j-1] )
  
  return max(data[0][n-1], data[1][n-1])

t = int(input())
t_print = []

for i in range(t):
  n = int(input())
  data = []
  for _ in range(2):
    data.append(list(map(int,input().split())))

  t_print.append ( sticker(n,data) )

for i in range(t):
  print( t_print[i] )

index 2 이상부터 2칸 전 대각선과 1칸 전 대각선 비교해서 더하기가 가능! 

# 11725

from collections import deque 

n = int(input()) # 노드의 수 

tree = [ [] for _ in range(n+1) ]
for i in range(n-1):
  a, b = map(int,input().split())
  tree[a].append(b)
  tree[b].append(a)

def bfs():

  q = deque()
  q.append(1)
  visited = [0] * (n+1)
  visited[1] = 1

  while q :
    x = q.popleft()
    for i in tree[x]:

      if visited[i] == False:
        visited[i] = x
        q.append(i)
  
  return visited
    
result = bfs()

for i in range(2,len(result)):
  print(result[i])

visited 리스트에 부모 노드를 저장함. 

1 -> 1과 연결된 것의 부모를 1로 설정하고 방문 처리한 뒤, queue에 넣음 -> 반복..