1068.md

1068

Python

# 내 풀이
def dfs(now):
    global ans
    if K == now:
        return
    if not tree[now]:
        ans += 1
        return
    for nxt in tree[now]:
        dfs(nxt)

N = int(input())
lst = list(map(int, input().split()))
tree = [[] for _ in range(N+1)]
K = int(input())

start = 0
for i, v in enumerate(lst):
    if v == -1:
        start = i
    elif i != K:
        tree[v].append(i)

ans = 0
dfs(start)

print(ans)

# 다른 사람 풀이
def dfs(now):
    lst[now] = -2
    for i in range(N):
        if lst[i] == now:
            dfs(i)

N = int(input())
lst = list(map(int, input().split()))
tree = [[] for _ in range(N+1)]
K = int(input())

dfs(K)
ans = 0
for i in range(N):
    if lst[i] != -2 and i not in lst:
        ans += 1

print(ans)