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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#50762#1256. Delete Two Vertices AgaintricyzhkxWA 15ms32212kbC++143.4kb2022-09-29 10:23:432022-09-29 10:23:46

Judging History

你现在查看的是最新测评结果

  • [2023-08-10 23:21:45]
  • System Update: QOJ starts to keep a history of the judgings of all the submissions.
  • [2022-09-29 10:23:46]
  • 评测
  • 测评结果:WA
  • 用时:15ms
  • 内存:32212kb
  • [2022-09-29 10:23:43]
  • 提交

answer

# include <bits/stdc++.h>
using namespace std;
int n,lc[6000010],rc[6000010],sum[6000010],rt[300010],bad[300010],L[300010],R[300010],dep[300010],top[300010],low[300010],minn[20][300010],fa[20][300010],tot;
char ans[300010];
struct Edge{int u,v;}e[300010];
vector<int> G[300010],T[300010],up[300010],E[300010];
bool vis[300010],ban[300010];
struct BIT
{
	int s[300010];
	void update(int x,int y){for(int i=x;i<=n;i+=i&(-i)) s[i]+=y;}
	void update(int l,int r,int x){update(l,x);update(r+1,-x);}
	int query(int x)
	{
		int ans=0;
		for(int i=x;i;i-=i&(-i)) ans+=s[i];
		return ans;
	}
}B;
void update(int &rt,int l,int r,int x)
{
	if(!rt) rt=++tot;
	if(l==r) return sum[rt]=1,void();
	int mid=(l+r)/2;
	if(x<=mid) update(lc[rt],l,mid,x);
	else update(rc[rt],mid+1,r,x);
	sum[rt]=sum[lc[rt]]+sum[rc[rt]];
}
int query(int rt,int l,int r,int x)
{
	if(l>x || !sum[rt]) return -1;
	if(l==r) return l;
	int mid=(l+r)/2,t;
	if(r<=x)
	{
		if(sum[rc[rt]]) return query(rc[rt],mid+1,r,x);
		else return query(lc[rt],l,mid,x);
	}
	if((t=query(rc[rt],mid+1,r,x))>0) return t;
	else return query(lc[rt],l,mid,x);
}
int merge(int x,int y,int l,int r)
{
	if(!x || !y) return x+y;
	if(l==r) return sum[x]|=sum[y],x;
	int mid=(l+r)/2;
	lc[x]=merge(lc[x],lc[y],l,mid);rc[x]=merge(rc[x],rc[y],mid+1,r);
	sum[x]=sum[lc[x]]+sum[rc[x]];
	return x;
}
void dfs1(int u)
{
	low[u]=dep[u];vis[u]=1;
	for(int v:G[u])
	{
		if(v==fa[0][u]) continue;
		if(!vis[v])
		{
			dep[v]=dep[u]+1;fa[0][v]=u;
			T[u].push_back(v);dfs1(v);
			low[u]=min(low[u],low[v]);
		}
		else if(dep[v]<dep[u]) up[u].push_back(dep[v]),low[u]=min(low[u],dep[v]);
	}
	top[u]=dep[u];
	for(int i:up[u]) top[u]=min(top[u],i);
}
void dfs2(int u)
{
	for(int v:T[u]) dfs2(v);
	bool ok=1;
	for(int v:T[u])
	{
		L[v]=low[v];R[v]=query(rt[v],1,n,dep[u]-1);
		rt[u]=merge(rt[u],rt[v],1,n);
		if(L[v]>R[v]) ok=0;
	}
	for(int i:up[u]) update(rt[u],1,n,i);
	for(int v:T[u])
		if(L[v]==R[v]) ban[L[v]]=1;
		else if(L[v]<R[v]) B.update(L[v]+1,R[v]-1,1);
	for(int i:E[u])
	{
		int v=e[i].v,w=u,mn=1e9;
		if(fa[0][u]==v && v==1)
		{
			if((int)T[v].size()>=2 && !T[u].empty()) ans[i]='0';
			else if(T[u].empty()) ans[i]=((int)T[v].size()<=2?'1':'0');
			else ans[i]=((int)T[u].size()<=1?'1':'0');
			continue;
		}
		if(!ok){ans[i]='0';continue;}
		if(fa[0][u]==v) mn=0;
		else
			for(int j=18;j>=0;j--)
				if(dep[fa[j][w]]>dep[v])
					mn=min(mn,minn[j][w]),w=fa[j][w];
		if(bad[v]-(low[w]>=dep[w]-1)>0 || ban[dep[v]]){ans[i]='0';continue;}
		if(v>1 && mn>=dep[v] && !B.query(dep[v])) ans[i]='0';
		else ans[i]='1';
	}
	for(int v:T[u])
		if(L[v]==R[v]) ban[L[v]]=0;
		else if(L[v]<R[v]) B.update(L[v]+1,R[v]-1,-1);
}
int main()
{
	low[0]=1e9;
	int m;
	cin>>n>>m;
	for(int i=1;i<=m;i++)
	{
		scanf("%d%d",&e[i].u,&e[i].v);
		G[e[i].u].push_back(e[i].v);G[e[i].v].push_back(e[i].u);
	}
	dep[1]=1;dfs1(1);
	for(int u=1;u<=n;u++)
	{
		int mn1=u,mn2=0;
		for(int v:T[u])
			if(low[v]<low[mn1]) mn2=mn1,mn1=v;
			else if(low[v]<low[mn2]) mn2=v;
		for(int v:T[u]) minn[0][v]=(v==mn1?low[mn2]:low[mn1]);
	}
	for(int i=1;i<=18;i++)
		for(int j=1;j<=n;j++)
			fa[i][j]=fa[i-1][fa[i-1][j]],
			minn[i][j]=min(minn[i-1][j],minn[i-1][fa[i-1][j]]);
	for(int i=2;i<=n;i++)
		if(low[i]>=dep[i]-1) bad[fa[0][i]]++;
	for(int i=1;i<=m;i++)
	{
		if(dep[e[i].u]<dep[e[i].v]) swap(e[i].u,e[i].v);
		E[e[i].u].push_back(i);
	}
	dfs2(1);
	printf("%s\n",ans+1);
	return 0;
}

Details

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Test #1:

score: 100
Accepted
time: 4ms
memory: 31916kb

input:

4 4
1 2
2 3
3 1
4 1

output:

0101

result:

ok OK. Jury's and participant's answers coincide. We don't know if they are both correct or both wrong.

Test #2:

score: 0
Accepted
time: 15ms
memory: 32048kb

input:

3 3
1 2
2 3
3 1

output:

111

result:

ok OK. Jury's and participant's answers coincide. We don't know if they are both correct or both wrong.

Test #3:

score: 0
Accepted
time: 8ms
memory: 32116kb

input:

3 2
1 2
2 3

output:

11

result:

ok OK. Jury's and participant's answers coincide. We don't know if they are both correct or both wrong.

Test #4:

score: 0
Accepted
time: 9ms
memory: 32160kb

input:

6 7
1 2
1 3
1 6
2 4
3 4
3 5
4 6

output:

1011011

result:

ok OK. Jury's and participant's answers coincide. We don't know if they are both correct or both wrong.

Test #5:

score: 0
Accepted
time: 0ms
memory: 32212kb

input:

10 39
1 2
1 3
1 5
1 6
1 7
1 8
1 9
1 10
2 3
2 4
2 5
2 6
2 9
2 10
3 5
3 6
3 7
3 8
3 10
4 5
4 6
4 7
4 9
4 10
5 6
5 7
5 8
5 9
5 10
6 7
6 8
6 9
6 10
7 8
7 9
7 10
8 9
8 10
9 10

output:

111111111111111111111111111111111111111

result:

ok OK. Jury's and participant's answers coincide. We don't know if they are both correct or both wrong.

Test #6:

score: -100
Wrong Answer
time: 8ms
memory: 32056kb

input:

10 12
1 6
1 7
2 5
2 8
3 4
3 6
4 6
4 10
5 9
5 10
6 9
7 10

output:

110111110011

result:

wrong answer Deleting vertices 4 and 6 makes graph disconnected, but participant claims otherwise.