結果

問題 No.2504 NOT Path Painting
ユーザー chineristACchineristAC
提出日時 2023-10-13 22:39:28
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 782 ms / 2,000 ms
コード長 2,137 bytes
コンパイル時間 340 ms
コンパイル使用メモリ 82,452 KB
実行使用メモリ 107,156 KB
最終ジャッジ日時 2024-09-15 18:24:47
合計ジャッジ時間 14,359 ms
ジャッジサーバーID
(参考情報)
judge5 / judge4
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ファイルパターン 結果
other AC * 21
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ソースコード

diff #
プレゼンテーションモードにする

import sys
from itertools import permutations
import heapq
from collections import deque
import random
input = lambda :sys.stdin.readline().rstrip()
mi = lambda :map(int,input().split())
li = lambda :list(mi())
mod = 998244353
def solve_brute(n,edge):
res = 1
deq = deque([0])
topo = []
parent = [-1] * n
while deq:
v = deq.popleft()
topo.append(v)
for nv in edge[v]:
if nv == parent[v]:
continue
parent[nv] = v
deq.append(nv)
sz = [1] * n
for v in topo[::-1]:
for nv in edge[v]:
if nv == parent[v]:
continue
sz[v] += sz[nv]
ok = n * (n+1)//2 - (n-sz[v]) * (n-sz[v]+1) //2
for nv in edge[v]:
if nv == parent[v]:
continue
ok -= sz[nv] * (sz[nv]+1) // 2
res += ok * pow(n*(n+1)//2-ok,mod-2,mod)
res %= mod
for v in range(1,n):
s = sz[v]
t = N - sz[v]
ok = s * t
res -= ok * pow(n*(n+1)//2-ok,mod-2,mod)
res %= mod
return res % mod
def brute(N):
def inv(r):
return pow(r,mod-2,mod)
dp = [[0]*N for i in range(N)]
for i in range(N):
k = i * (i+1) //2 + (N-i-1) * (N-i)//2
dp[i][i] = N*(N+1)//2 * pow(k,mod-2,mod) % mod
for l in range(N)[::-1]:
for r in range(l+1,N):
a,b = 0,0
for x in range(N):
for y in range(x,N):
nl,nr = max(l,x),min(r,y)
if (nl,nr)!=(l,r):
b += dp[nl][nr] * inv(N*(N+1)//2)
b %= mod
else:
a += 1
dp[l][r] = (b+1) * inv(1-(a * inv(N*(N+1)//2))) % mod
return dp[0][N-1]
for _ in range(int(input())):
N = int(input())
edge = [[] for v in range(N)]
for _ in range(N-1):
u,v = mi()
edge[u-1].append(v-1)
edge[v-1].append(u-1)
print(solve_brute(N,edge))
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