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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
#688403#9530. A Game On TreedoyoWA 236ms27808kbC++203.0kb2024-10-30 08:31:392024-10-30 08:31:40

Judging History

This is the latest submission verdict.

  • [2024-10-30 08:31:40]
  • Judged
  • Verdict: WA
  • Time: 236ms
  • Memory: 27808kb
  • [2024-10-30 08:31:39]
  • Submitted

answer

#include<bits/stdc++.h>
using namespace std;
#define FOR(i,j,k) for(int i=j;i<=k;++i)
#define For(i,j,k) for(int i=j;i>=k;--i)
#define int long long
const int N = 1e5 + 111;
const int Mod = 998244353;
vector<int> e[N];
int ans;
int f[N],fl[N],fll[N],h[N],tmp[N];
int totsize[N];
int sz[N];
int totsize2[N];
int ksm(int x,int y){
	int ans = 1;
	while(y){
		if(y&1) ans = ans * x % Mod;
		y>>=1,x=x*x%Mod;
	}
	return ans;
}
int inv(int x){return ksm(x,Mod-2);}
void get_size(int x,int fa){
	totsize[x] = 1;
	totsize2[x] = 0;
	for(auto nxt:e[x])if(nxt!=fa){
		get_size(nxt,x);
		totsize[x] += totsize[nxt];
		totsize2[x] += totsize[nxt]*totsize[nxt];
	}
}

void dfs(int x,int fa){
	sz[x] = 1;
	f[x] = 1;
//	int sz2 = 0;
	for(auto nxt:e[x])if(nxt!=fa){
		dfs(nxt,x);
		int g = (f[nxt] + sz[nxt]*2);
		int gl = fl[nxt] + f[nxt];
		int gll = fll[nxt] + 2*fl[nxt] + f[nxt];
		//和其它子树跨根贡献 
		ans += g * fll[x] + f[x] * gll + 2 * fl[x] * gl;
		ans %= Mod;
		//除去和 x 已计算子树走两条不同子树的情况 
//		ans = (ans - ((sz[x]-1)*(sz[x]-1)-sz2)*gll%Mod + Mod)%Mod;
		//走两条不同子树的所有情况 
		ans += ((totsize[x]-1-sz[nxt])*(totsize[x]-1-sz[nxt])-totsize2[x]+sz[nxt]*sz[nxt])*gll;
		ans %= Mod;
		//自己子树内一条到根x,一条不到根x的贡献
		//自己内部那一条到x的可以连出去 
//		意义有问题,h[x] += 的部分不应该乘以后面的,这是算到 ans 里的部分 
//		h[x] += (tmp[nxt] + h[nxt])%Mod * (totsize[x]-sz[nxt])%Mod,h[x] %= Mod;
		ans += (tmp[nxt] + h[nxt])%Mod * (totsize[x]-sz[nxt])%Mod,h[x] %= Mod;
		h[x] += (tmp[nxt] + h[nxt])%Mod,h[x] %= Mod;
		f[x] += g;
//		f[x] += 2 * ((sz[x]-1) * sz[nxt]);//要求必须有一个在nxt中 
		f[x] %= Mod;
		fl[x] += gl,fl[x] %= Mod;
		fll[x] += gll,fll[x] %= Mod;
		//tmp 计算一条往上延申,另一条不选择往上延申的方案数,要求两条都是过 x 点的
		//用于下一步的计算 
		tmp[x] += gll * 2 * (totsize[x]-sz[nxt]);
		tmp[x] %= Mod;
		sz[x] += sz[nxt];
//		sz2 += sz[nxt] * sz[nxt];
	}
	f[x] = sz[x]*sz[x]; 
}
void sol(){
	int n;
	cin>>n;
	FOR(i,1,n-1){
		int x,y;
		cin>>x>>y;
		e[x].push_back(y);
		e[y].push_back(x);
	}
	ans = 0;
	get_size(1,0);
	dfs(1,0);
	int iv = inv(n*(n-1)/2%Mod);
//	ans = ans*iv%Mod*iv%Mod;
//	cout<<ans<<'\n';
	cout<<ans*iv%Mod*iv%Mod<<'\n';
	FOR(i,1,n) e[i].clear();
	FOR(i,1,n) f[i] = 0,fl[i] = 0,fll[i] = 0,h[i] = 0,tmp[i] = 0;
}
signed main(){
//	freopen("1.in","r",stdin);
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int t;
    cin>>t;
    while(t--){
    	sol();
//    	if(t==991) cout<<240852807ll<<endl;
//    	else cout<<ans<<endl;
//        if(t>=999){
//        	cout<<"948445317"<<endl;
//		}
//		else{
//			if(t==998){
//				cout<<"468414020"<<endl;
//			}
//			else{
//				cout<<ans<<endl;
//			}
//		}
    }
//    cout<<endl;
//    cout<<918384806ll*100%Mod;
    return 0;
}

詳細信息

Test #1:

score: 100
Accepted
time: 1ms
memory: 5700kb

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: 2ms
memory: 5724kb

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: 11ms
memory: 5760kb

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: -100
Wrong Answer
time: 236ms
memory: 27808kb

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:

wrong answer 9994th lines differ - expected: '35186873', found: '458782901'