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#20373#2214. Link Cut Digraph2018ty22#ML 0ms0kbC++202.0kb2022-02-15 21:47:322022-05-03 09:45:58

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.
  • [2022-05-03 09:45:58]
  • 评测
  • 测评结果:ML
  • 用时:0ms
  • 内存:0kb
  • [2022-02-15 21:47:32]
  • 提交

answer

#include<algorithm>
#include<cstdio>
#define ll long long
#define min(a,b) (a<b?a:b)
using namespace std;
struct node{
	int x,y,t;
}b[250001];
int n,m,fa[100001],siz[100001];
int head[100001],s[100001],nxt[100001];
int dfn[100001],lst[100001],tot;
int st[100001],top;
int p[100001],cp[100001];
ll ans;
bool cmp(node x,node y){return x.t<y.t;}
int find(int x)
{
	if(fa[x])return fa[x]=find(fa[x]);
	return x;
}
void tarjan(int x,int f1)
{
	dfn[x]=lst[x]=++tot;
	for(int i=head[x];i;i=nxt[i])
		if(i!=f1)
		{
			if(!dfn[s[i]])tarjan(s[i],i);
			lst[x]=min(lst[x],lst[s[i]]);
		}
	if(lst[x]<dfn[x])st[++top]=x;
	else
	{
		while(lst[st[top]]>=dfn[x])
		{
			int x1=find(st[top]),x2=find(x);
			fa[x1]=x2;--top;
		}
	}
}
void solve(int l,int r,int l1,int r1)
{
	if(l==r||l1>r1)return;
	int mid=l+r>>1,num=0;tot=0;
	for(int i=l1;i<=r1&&b[p[i]].t<=mid;++i)
	{
		head[b[p[i]].x]=head[b[p[i]].y]=0;
		dfn[b[p[i]].x]=dfn[b[p[i]].y]=0;
		fa[b[p[i]].x]=fa[b[p[i]].y]=0;
	}
	for(int i=l1;i<=r1&&b[p[i]].t<=mid;++i)
		s[++num]=b[p[i]].y,
		nxt[num]=head[b[p[i]].x],
		head[b[p[i]].x]=num;
	for(int i=l1;i<=r1&&b[p[i]].t<=mid;++i)
		if(!dfn[b[p[i]].x])
			tarjan(b[p[i]].x,-1);
	int n1=l1-1,n2=0;
	for(int i=l1;i<=r1;++i)
		if(b[p[i]].t<=mid&&find(b[p[i]].x)==find(b[p[i]].y))
			p[++n1]=p[i];
		else
		{
			b[p[i]].x=find(b[p[i]].x);
			b[p[i]].y=find(b[p[i]].y);
			if(b[p[i]].t<=mid)b[p[i]].t=mid+1;
			cp[++n2]=p[i];
		}
	for(int i=1;i<=n2;++i)p[n1+i]=cp[i];
	solve(l,mid,l1,n1);
	solve(mid+1,r,n1+1,r1);
}
int main()
{
	scanf("%d%d",&n,&m);
	for(int i=1;i<=m;++i)
		scanf("%d%d",&b[i].x,&b[i].y),b[i].t=i,p[i]=i;
	solve(1,m,1,n);
	for(int i=1;i<=n;++i)fa[i]=0,siz[i]=1;
	sort(b+1,b+m+1,cmp);
	for(int i=1,j=1;i<=m;++i)
	{
		while(j<=m&&b[j].t<=i)
		{
			int x=find(b[j].x),y=find(b[j].y);
			if(x!=y)
			{
				ans+=(ll)((siz[x]+siz[y])*(siz[x]+siz[y]-1))-(ll)siz[x]*(siz[x]-1)-(ll)siz[y]*(siz[y]-1);
				siz[x]+=siz[y];
				fa[y]=x;
			}
			++j;
		}
		printf("%lld\n",ans>>1ll);
	}
}

详细

Test #1:

score: 0
Memory Limit Exceeded