QOJ.ac

QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#464514#5437. Graph CompletingEthanDongWA 88ms203344kbC++141.6kb2024-07-06 10:50:362024-07-06 10:50:36

Judging History

你现在查看的是最新测评结果

  • [2024-07-06 10:50:36]
  • 评测
  • 测评结果:WA
  • 用时:88ms
  • 内存:203344kb
  • [2024-07-06 10:50:36]
  • 提交

answer

#include <cstdio>
#include <vector>
#include <stack>
#include <cstring>
using namespace std;
const int MOD=998244353;
int clo,dfn[5007],low[5007],vis[5007],tot,sz[5007],cnt[5007];
long long jc[25000007],dp[5007][5007],f[5007];
stack<int> st;
vector<int> g[5007],e[5007];
void tarjan(int u,int fa){
	dfn[u]=low[u]=++clo;
	st.push(u);
	for(int i=0;i<g[u].size();i++){
		int v=g[u][i];
		if(v==fa) continue;
		if(!dfn[v]){
			tarjan(v,u);
			low[u]=min(low[u],low[v]);
		}else low[u]=min(low[u],dfn[v]);
	}
	if(dfn[u]==low[u]){
		tot++;
		while(st.top()!=u){
			int x=st.top();
			st.pop();
			sz[tot]++;
			vis[x]=tot;
		}
		int x=st.top();
		st.pop();
		sz[tot]++;
		vis[x]=tot;
	}
}
void dfs(int u,int fa){
	dp[u][sz[u]]=jc[sz[u]*(sz[u]-1)/2-cnt[u]];
	for(int i=0;i<e[u].size();i++){
		int v=e[u][i];
		if(v==fa) continue;
		dfs(v,u);
		memset(f,0,sizeof(f));
		for(int j=1;j<=sz[u];j++){
			for(int k=1;k<=sz[v];k++){
				f[j]=(f[j]-dp[u][j]*dp[v][k]%MOD+MOD)%MOD;
				(f[j+k]+=(dp[u][j]*dp[v][k]%MOD)*jc[j*k-1]%MOD)%=MOD;
			}
			dp[u][j]=f[j];
		}
		sz[u]+=sz[v];
	}
}
int x[5007],y[5007],lg[5007][5007];
int main(){
	jc[0]=1;
	for(int i=1;i<=25000000;i++) jc[i]=jc[i-1]*2%MOD;
	int n,m;
	scanf("%d%d",&n,&m);
	for(int i=1;i<=m;i++){
		scanf("%d%d",&x[i],&y[i]);
		g[x[i]].push_back(y[i]);
		g[y[i]].push_back(x[i]);
	}
	tarjan(1,0);
	for(int i=1;i<=m;i++){
		int u=x[i],v=y[i];
		if(vis[u]==vis[v]) cnt[vis[u]]++;
		else{
			e[vis[u]].push_back(vis[v]);
			e[vis[v]].push_back(vis[u]);
		}
	}
	dfs(1,0);
	long long ans=0;
	for(int i=1;i<=sz[1];i++) (ans+=dp[1][i])%=MOD;
	printf("%lld",ans);
	return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 76ms
memory: 201992kb

input:

3 2
1 2
2 3

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 88ms
memory: 201520kb

input:

4 4
1 2
2 3
3 4
4 1

output:

4

result:

ok 1 number(s): "4"

Test #3:

score: -100
Wrong Answer
time: 83ms
memory: 203344kb

input:

2 1
1 2

output:

998244352

result:

wrong answer 1st numbers differ - expected: '0', found: '998244352'