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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#873493#9530. A Game On TreeMini_PEKKAWA 178ms21756kbC++201.6kb2025-01-26 15:29:372025-01-26 15:29:37

Judging History

This is the latest submission verdict.

  • [2025-01-26 15:29:37]
  • Judged
  • Verdict: WA
  • Time: 178ms
  • Memory: 21756kb
  • [2025-01-26 15:29:37]
  • Submitted

answer

#include <bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
#define sz(a) (ll)a.size()
#define lb(x) (x&-x)
#define rep(i,a,b) for(ll i=(a);i<=(b);i++)
#define per(i,a,b) for(ll i=(a);i>=(b);i--)
using namespace std;
using ll=long long;
using ull=unsigned long long;
using db=double;
using pll=pair<ll,ll>;
//using i128=__int128;
template<typename T> constexpr bool cmax(T &a,const T &b){return b>a?a=b,1:0;}
template<typename T> constexpr bool cmin(T &a,const T &b){return b<a?a=b,1:0;}
constexpr ll N=100010;
constexpr ll mod=998244353;
ll n,ans,sz[N],fa[N],s[N];
vector<ll> T[N];
ll sq(ll x){
	return x*x%mod;
}
ll qpow(ll a,ll b=mod-2){
	ll ans=1;
	for(;b>0;b/=2,(a*=a)%=mod){
		if(b%2==1){
			(ans*=a)%=mod;
		}
	}
	return ans;
}
void dfs(ll u){
	sz[u]=1;
	ll ss=0;
	for(ll v:T[u]){
		if(v==fa[u]){
			continue;
		}
		fa[v]=u;
		dfs(v);
		sz[u]+=sz[v];
		(ss+=s[v])%=mod;
	}
	s[u]=(ss+sq(sz[u]))%mod;
	for(ll v:T[u]){
		if(v==fa[u]){
			continue;
		}
		(ans+=sq(sz[v])*sq(n-sz[v]))%=mod;
		(ans+=2*sq(n-sz[v])*(s[v]-sq(sz[v])))%=mod;
		(ans+=s[v]*(ss-s[v]))%=mod;
	}
}
void solve(){
	cin>>n;
	rep(i,1,n){
		T[i].clear();
	}
	rep(i,1,n-1){
		ll u,v;
		cin>>u>>v;
		T[u].pb(v);
		T[v].pb(u);
	}
	ans=0;
	dfs(1);
	ll ip=qpow(n*(n-1)/2%mod);
	cout<<ans*sq(ip)%mod<<'\n';
}
int main(){
	ios::sync_with_stdio(0),cin.tie(0);
//	freopen("test.in","r",stdin);
//	freopen("test.out","w",stdout);
	ll t;
	cin>>t;
	rep(i,1,t){
		solve();
	}
	return 0;
}
/**
 * typeperf "\Process(test)\Working Set Peak" -si 2
 * TODO: delete while(1);
 * TODO: multitest cleanup
 */

詳細信息

Test #1:

score: 100
Accepted
time: 0ms
memory: 5864kb

input:

2
3
1 2
2 3
5
1 2
1 5
3 2
4 2

output:

443664158
918384806

result:

ok 2 lines

Test #2:

score: 0
Accepted
time: 0ms
memory: 5684kb

input:

1000
7
3 6
4 3
5 3
2 6
1 4
7 1
12
5 7
10 7
2 10
11 2
1 7
8 1
4 2
9 11
6 9
12 11
3 5
6
2 5
1 2
4 5
6 4
3 6
5
2 5
1 5
4 5
3 2
8
1 8
2 8
4 2
6 1
5 6
7 6
3 8
8
3 8
7 3
4 8
6 4
2 7
5 2
1 4
4
3 1
4 3
2 1
6
5 1
6 1
2 5
3 5
4 2
12
8 11
5 11
12 8
3 12
6 12
2 3
4 6
10 11
1 5
9 5
7 5
9
6 1
7 6
4 7
8 7
5 4
9 6
...

output:

948445317
468414020
550143557
918384806
711758412
487662742
776412276
869581749
240852807
765628773
211048577
887328316
890334966
940494682
760637552
908032643
592850815
584006902
908525604
221832080
433351719
56023919
867301808
183319566
698771049
366957926
449579681
599710576
310564911
286902823
3...

result:

ok 1000 lines

Test #3:

score: 0
Accepted
time: 6ms
memory: 5748kb

input:

1000
94
59 1
33 59
73 1
6 33
83 59
4 59
20 59
61 6
39 1
76 73
71 6
44 39
9 71
24 4
87 9
57 83
2 9
81 71
82 20
90 2
85 39
12 9
30 83
66 30
53 9
47 9
36 44
43 53
29 12
31 53
64 81
38 31
84 82
77 38
23 71
93 84
78 83
58 31
68 90
42 1
55 64
13 78
70 78
62 24
19 55
92 87
14 57
10 84
65 81
63 6
75 36
91 1...

output:

508107725
996793960
201633249
335988372
842755864
460619380
342223697
207523414
429241811
391691799
542977964
786416604
454278948
685531402
25914978
440729774
228518323
679471537
82764520
554190841
432505337
143444089
189106586
337234245
61954935
905141094
532919674
703954588
185671863
942858630
692...

result:

ok 1000 lines

Test #4:

score: 0
Accepted
time: 178ms
memory: 21504kb

input:

10000
8
1 4
3 1
5 1
7 3
8 4
6 8
2 7
8
2 6
4 6
5 6
8 5
7 6
3 5
1 7
8
8 5
6 5
2 5
7 2
1 6
3 1
4 8
9
8 6
9 8
3 6
1 8
5 9
2 8
4 3
7 9
8
8 6
3 6
5 8
1 6
4 3
7 6
2 6
9
9 5
7 5
2 7
8 7
4 9
3 7
6 3
1 4
8
1 4
5 1
6 5
3 4
8 4
7 8
2 5
9
1 8
6 1
2 1
3 8
5 3
9 8
7 8
4 8
9
4 9
2 9
1 2
3 4
5 2
6 9
8 3
7 2
8
1 2
8 ...

output:

49657566
56023919
387074343
97051536
701572244
211048577
711758412
308100110
761007271
711758412
178698065
285212675
80216065
43380497
267677376
818005792
53239701
765628773
970145625
387074343
436731906
422725927
479157293
977872021
436731906
925779210
487662742
705549251
267677376
711758412
526851...

result:

ok 10000 lines

Test #5:

score: 0
Accepted
time: 175ms
memory: 21504kb

input:

10000
8
7 6
8 6
5 7
4 6
1 4
2 5
3 5
10
10 7
8 7
9 8
2 8
6 7
1 7
5 9
4 1
3 6
10
2 6
3 6
5 6
7 2
1 3
4 5
8 5
9 5
10 4
10
6 5
2 5
4 6
8 5
10 5
9 5
1 8
3 6
7 1
8
5 2
3 5
6 5
1 2
8 2
4 1
7 5
9
5 1
3 1
7 5
9 7
6 3
8 6
2 1
4 9
9
9 8
4 8
3 8
6 9
2 8
7 6
1 2
5 6
9
2 5
8 5
7 8
9 7
1 8
4 8
6 9
3 1
8
6 7
8 6
2 ...

output:

711758412
286902823
691130166
841483019
650641410
887328317
331207619
733278261
56023919
977872021
414394648
183319566
239374924
696059768
855285904
761007271
711758412
86268032
599710576
728310932
178698065
178698065
422725927
219002589
178698065
202450068
599710576
56023919
449579681
760637552
925...

result:

ok 10000 lines

Test #6:

score: -100
Wrong Answer
time: 173ms
memory: 21756kb

input:

10000
9
8 1
2 8
4 1
3 2
7 1
6 7
9 3
5 1
9
7 5
1 7
3 7
9 5
2 3
8 1
6 8
4 6
9
7 8
4 7
5 4
3 4
6 8
1 3
9 8
2 7
9
8 7
2 8
9 8
5 8
1 2
3 7
6 3
4 7
8
6 8
4 6
2 4
5 8
7 5
1 6
3 7
9
9 8
7 8
2 9
5 9
1 5
3 1
6 2
4 8
10
2 10
4 10
6 4
1 10
9 6
8 9
5 10
7 4
3 2
10
3 9
5 3
4 3
7 9
6 3
10 6
2 9
8 5
1 2
10
8 5
2 8
...

output:

211048577
354315128
178698065
705549251
285212675
138645051
449579681
286902823
925779210
294297225
519087065
368179632
422725927
603876215
539175192
867301808
977540027
669439919
211048577
701572244
977872021
138645051
267677376
855285904
977872021
286902823
925286249
705549251
219002589
331207619
...

result:

wrong answer 9994th lines differ - expected: '649995321', found: '-348249032'