Submission #1845274


Source Code Expand

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cassert>
#include <cctype>
#include <algorithm>
using namespace std;
typedef long long lint;
#define cout cerr
#define ni (next_num<int>())
template<class T>inline T next_num(){
	T i=0;char c;
	while(!isdigit(c=getchar())&&c!='-');
	bool flag=c=='-';
	flag?c=getchar():0;
	while(i=i*10-'0'+c,isdigit(c=getchar()));
	return flag?-i:i;
}
template<class T1,class T2>inline void apmax(T1 &a,const T2 &b){if(a<b)a=b;}
template<class T1,class T2>inline void apmin(T1 &a,const T2 &b){if(b<a)a=b;}
const int N=20010;
int n,cup;
int x[N],lst[N];
namespace G{
	const int N=20010*4,E=(N<<3)+N*40;//todo
	int to[E],bro[E],head[N],e,n;
	int dfn[N],low[N],bln[N],tim;
	inline int nn(){
		return ++n;
	}
	inline void init(){
		memset(head+1,-1,n<<2);
		memset(dfn+1,0,n<<2);
		e=tim=0;
	}
	inline void ae(int u,int v){
		to[e]=v,bro[e]=head[u],head[u]=e++;
	}
	int stk[N],ss=0;
	bool instk[N];
	void tarjan(int x){
		dfn[x]=low[x]=++tim;
		stk[ss++]=x,instk[x]=true;
		for(int i=head[x],v;~i;i=bro[i]){
			if(dfn[v=to[i]]){
				if(instk[v]){
					apmin(low[x],dfn[v]);
				}
			}else{
				tarjan(v);
				apmin(low[x],low[v]);
			}
		}
		if(dfn[x]==low[x]){
			int v;
			do{
				v=stk[--ss];
				instk[v]=false;
				bln[v]=x;
			}while(v!=x);
		}
	}
}
namespace seg{
	struct Node;
	typedef Node* node;
	struct Node{
		int l,m,r;
		node lson,rson;
		int p[2];
	}*rt;
	node build(int l,int r){
		static node n=new Node[N<<1];
		node x=n++;
		x->l=l,x->m=(l+r)>>1,x->r=r;
		if(l==r){
			x->p[0]=lst[l],x->p[1]=cup-lst[l];
		}else{
			x->p[0]=G::nn(),x->p[1]=G::nn();
			x->lson=build(l,x->m);
			x->rson=build(x->m+1,r);
		}
		return x;
	}
	void putedge(node x){
		if(x->l!=x->r){
			G::ae(x->p[1],x->lson->p[1]);
			G::ae(x->lson->p[0],x->p[0]);
			G::ae(x->p[1],x->rson->p[1]);
			G::ae(x->rson->p[0],x->p[0]);
			putedge(x->lson);
			putedge(x->rson);
		}
	}
	void ae(node x,int p,int l,int r){
		if(x->l==l&&x->r==r){
			G::ae(p,x->p[1]);
			G::ae(x->p[0],cup-p);
		}else if(r<=x->m){
			ae(x->lson,p,l,r);
		}else if(x->m<l){
			ae(x->rson,p,l,r);
		}else{
			ae(x->lson,p,l,x->m);
			ae(x->rson,p,x->m+1,r);
		}
	}
}
inline bool judge(int d){
	G::init();
	seg::putedge(seg::rt);
	for(int i=1,j=i;i<cup;i++){
		for(;x[lst[i]]-x[lst[j]]>=d;j++);
		if(j<i){
			seg::ae(seg::rt,lst[i],j,i-1);
		}
	}
	for(int i=1;i<=G::n;i++){
		if(G::dfn[i]==0){
			G::tarjan(i);
		}
	}
	for(int i=1;i<cup;i++){
		if(G::bln[i]==G::bln[cup-i])return false;
	}
	for(int i=cup;i<=G::n;i+=2){
		if(G::bln[i]==G::bln[i+1])return false;
	}
	return true;
}
inline bool lcmp(int a,int b){
	return x[a]<x[b];
}
inline int Main(){
	n=ni,cup=(n<<1)+1;
	for(int i=1;i<=n;i++){
		x[i]=ni,x[cup-i]=ni;
	}
	for(int i=1;i<cup;i++){
		lst[i]=i;
	}
	sort(lst+1,lst+cup,lcmp);
	G::n=n<<1;
	seg::rt=seg::build(1,n<<1);
	int l=0,r=x[lst[cup-1]]-x[lst[1]];
	while(l<r){
		int m=((l+r)>>1)+1;
		if(judge(m)){
			l=m;
		}else{
			r=m-1;
		}
	}
	return l;
}
int main(){
	printf("%d\n",Main());
	return 0;
}

Submission Info

Submission Time
Task F - Flags
User sshockwave
Language C++14 (GCC 5.4.1)
Score 1200
Code Size 3173 Byte
Status AC
Exec Time 299 ms
Memory 13568 KB

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 1200 / 1200
Status
AC × 3
AC × 30
Set Name Test Cases
Sample 00_example_01.txt, 00_example_02.txt, 00_example_03.txt
All 00_example_01.txt, 00_example_02.txt, 00_example_03.txt, 01.txt, 02.txt, 03.txt, 04.txt, 05.txt, 06.txt, 07.txt, 08.txt, 09.txt, 10.txt, 11.txt, 12.txt, 13.txt, 14.txt, 15.txt, 16.txt, 17.txt, 18.txt, 19.txt, 20.txt, 21.txt, 22.txt, 23.txt, 24.txt, 25.txt, 26.txt, 27.txt
Case Name Status Exec Time Memory
00_example_01.txt AC 2 ms 2304 KB
00_example_02.txt AC 1 ms 256 KB
00_example_03.txt AC 2 ms 2304 KB
01.txt AC 5 ms 2560 KB
02.txt AC 3 ms 2432 KB
03.txt AC 2 ms 2304 KB
04.txt AC 2 ms 2304 KB
05.txt AC 2 ms 2432 KB
06.txt AC 162 ms 9472 KB
07.txt AC 161 ms 9344 KB
08.txt AC 162 ms 9344 KB
09.txt AC 5 ms 2560 KB
10.txt AC 3 ms 2432 KB
11.txt AC 2 ms 2304 KB
12.txt AC 2 ms 2304 KB
13.txt AC 2 ms 2432 KB
14.txt AC 161 ms 11392 KB
15.txt AC 160 ms 11392 KB
16.txt AC 160 ms 11392 KB
17.txt AC 6 ms 2560 KB
18.txt AC 3 ms 2432 KB
19.txt AC 177 ms 9344 KB
20.txt AC 177 ms 9344 KB
21.txt AC 222 ms 11392 KB
22.txt AC 223 ms 11392 KB
23.txt AC 299 ms 13440 KB
24.txt AC 200 ms 13440 KB
25.txt AC 251 ms 13568 KB
26.txt AC 201 ms 11392 KB
27.txt AC 2 ms 2304 KB