結果

問題 No.1418 Sum of Sum of Subtree Size
ユーザー convexineqconvexineq
提出日時 2021-03-05 22:05:39
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 349 ms / 2,000 ms
コード長 2,353 bytes
コンパイル時間 357 ms
コンパイル使用メモリ 81,792 KB
実行使用メモリ 105,952 KB
最終ジャッジ日時 2024-10-07 02:02:05
合計ジャッジ時間 8,755 ms
ジャッジサーバーID
(参考情報)
judge1 / judge2
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 41
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

def rerooting(g,e_M):
"""
"""
def merge(x,y): # x y
return (x[0]+y[0],x[1]+y[1])
def h1(x,v): # x = dp[v][p] v->p
return (x[0]+1,x[1]+x[0]+2)
#def h2(x,p,v): # x = dp[p][v] p->v
# v p
def h2(x,p,v): return h1(x,p)
h_fin = lambda x:x
"""
dfs_bottom_up: DP
dfs_top_down: rerooting
"""
def get_order(g):
n = len(g)
order = []
st = [0]
parent = [-1]*n
while st:
v = st.pop()
order.append(v)
for c in g[v]:
if c != parent[v]:
st.append(c)
parent[c] = v
return order, parent
def dfs_bottom_up(BU,hBU,parent,order):
for i in order[::-1]:
hBU[i] = h1(BU[i], i)
if i: BU[parent[i]] = merge(BU[parent[i]], hBU[i])
def dfs_top_down(hBU,hTD,g,parent,order):
for v in order:
acc_l = e_M
for c in g[v]:
if c==parent[v]:
acc_l = merge(acc_l,hTD[v])
else:
hTD[c] = acc_l
acc_l = merge(acc_l,hBU[c])
acc_r = e_M
for c in g[v][::-1]:
if c==parent[v]:
acc_r = merge(hTD[v],acc_r)
else:
hTD[c] = h2(merge(hTD[c],acc_r),parent[v],v)
acc_r = merge(acc_r,hBU[c])
order, parent = get_order(g)
BU = [e_M]*n
hBU = [e_M]*n
hTD = [e_M]*n
dfs_bottom_up(BU,hBU,parent,order)
dfs_top_down(hBU,hTD,g,parent,order)
for i in range(n):
BU[i] = h_fin(merge(BU[i],hTD[i]))
return BU
#######################################
# https://atcoder.jp/contests/dp/submissions/17723902
#######################################
# coding: utf-8
# Your code here!
import sys
readline = sys.stdin.readline
read = sys.stdin.read
n = int(input())
g = [[] for _ in range(n)]
for _ in range(n-1):
a,b = map(int,readline().split())
g[a-1].append(b-1)
g[b-1].append(a-1)
ans = n
for i,j in rerooting(g,(0,0)):
ans += j
print(ans)
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