結果

問題 No.1333 Squared Sum
ユーザー toyuzuko
提出日時 2021-04-17 23:11:53
言語 PyPy3
(7.3.15)
結果
WA  
実行時間 -
コード長 2,613 bytes
コンパイル時間 282 ms
コンパイル使用メモリ 82,600 KB
実行使用メモリ 210,852 KB
最終ジャッジ日時 2024-07-04 04:17:42
合計ジャッジ時間 39,729 ms
ジャッジサーバーID
(参考情報)
judge4 / judge2
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
other AC * 25 WA * 19
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

class Tree():
def __init__(self, n):
self.n = n
self.tree = [[] for _ in range(n)]
self.cost = dict()
self.root = None
def add_edge(self, u, v, c):
if u > v: u, v = v, u
self.tree[u].append(v)
self.tree[v].append(u)
self.cost[u * self.n + v] = c
def get_cost(self, u, v):
if u is None or v is None:
return 0
if u < v:
return self.cost[u * self.n + v]
else:
return self.cost[v * self.n + u]
def set_root(self, r=0):
self.root = r
self.par = [None] * self.n
self.ord = [r]
stack = [r]
while stack:
v = stack.pop()
for adj in self.tree[v]:
if self.par[v] == adj: continue
self.par[adj] = v
self.ord.append(adj)
stack.append(adj)
def rerooting(self, op, e, merge, id):
if self.root is None: self.set_root()
dp = [e] * self.n
lt = [id] * self.n
rt = [id] * self.n
inv = [id] * self.n
for v in self.ord[::-1]:
tl = tr = e
for adj in self.tree[v]:
if self.par[v] == adj: continue
lt[adj] = tl
self.w = self.get_cost(v, adj)
tl = op(tl, dp[adj])
for adj in self.tree[v][::-1]:
if self.par[v] == adj: continue
rt[adj] = tr
self.w = self.get_cost(v, adj)
tr = op(tr, dp[adj])
dp[v] = tr
for v in self.ord:
if v == self.root: continue
p = self.par[v]
pp = self.par[p]
self.w = self.get_cost(p, pp)
inv[v] = op(merge(lt[v], rt[v]), inv[p])
self.w = self.get_cost(v, p)
dp[v] = op(dp[v], inv[v])
return dp
import sys
input = sys.stdin.buffer.readline
MOD = 1000000007
N = int(input())
t = Tree(N)
for _ in range(N - 1):
u, v, w = map(int, input().split())
u -= 1; v -= 1
t.add_edge(u, v, w)
e = (1, 0, 0)
def op(p, c):
ps, pd, pds = p
cs, cd, cds = c
size = ps + cs
w = t.w
dist = (pd + cd + w * cs) % MOD
dsq = (pds + cds + w**2 * cs + 2 * w * cd) % MOD
return size, dist, dsq
id = (0, 0, 0)
def merge(lt, rt):
ls, ld, lds = lt
rs, rd, rds = rt
size = ls + rs - 1
dist = (ld + rd) % MOD
dsq = (lds + rds) % MOD
return size, dist, dsq
dp = t.rerooting(op, e, merge, id)
res = 0
for i in range(N):
res += dp[i][2]
res %= MOD
print(res // 2)
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
0