Submission #410343

#	Time	Username	Problem	Language	Result	Execution time	Memory
410343		nathanlee726	Meetings (JOI19_meetings)	C++14	100 / 100	1020 ms	1060 KiB

meetings

//#include<i_am_noob_orz>
#include<bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
#define ll long long
//#define int ll
#define ull unsigned long long
#define pii pair<int,int>
#define X first
#define Y second
#define mod ((ll)1e9+7)
#define pb push_back
#define mp make_pair
#define abs(x) ((x)>0?(x):(-(x)))
#define F(n) Fi(i,n)
#define Fi(i,n) Fl(i,0,n)
#define Fl(i,l,n) for(int i=l;i<n;i++)
#define memres(a) memset(a,0,sizeof(a))
#define all(a) a.begin(),a.end()
#define sz(a) ((int)a.size())
#define ceiling(a,b) (((a)+(b)-1)/(b))
#define endl '\n'
#define bit_count(x) __builtin_popcountll((x))
#define ykh mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define jimmy_is_kind false
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> rbtree;
 
//#define LOCAL
#ifdef LOCAL
#define bug(...) cerr<<"#"<<__LINE__<<' '<<#__VA_ARGS__<<"- ", _do(__VA_ARGS__)
template<typename T> void _do(T && x) {cerr<<x<<endl;}
template<typename T, typename ...S> void _do(T && x, S&&...y) {cerr<<x<<", "; _do(y...);}
#define IOS()
int Query(int x,int y,int z){return x;}
void Bridge(int u,int v){cout<<u<<" "<<v<<endl;}
#else
#include<meetings.h> 
#define IOS() ios_base::sync_with_stdio(0), cin.tie(0)
#define endl '\n'
#define bug(...)
#endif
 
int add(int a,int b){return(a+b>=mod?a+b-mod:a+b);}
int sub(int a,int b){return(a<b?a+mod-b:a-b);}
int po(int a,int b){
	if(b==0)return 1;
	if(b==1)return(a%mod);
	int tem=po(a,b/2);
	if(b&1)return(((tem*tem)%mod)*a)%mod;
	else return(tem*tem)%mod; 
}
int GCD(int a,int b){
	int x=0;
	int ra,rb;
	while(a&&b){
		if(((a&1)==0)&&((b&1)==0)){
			a>>=1,b>>=1,x++;
		}
		else if((a^b)&1){
			if(a&1)b>>=1;
			else a>>=1;
		}
		else{
			ra=abs(a-b),rb=min(a,b);
			a=ra,b=rb;
		}
	}
	return max(a,b)<<x;
}
int gcd(int a,int b){if(b==0)return a;return gcd(b,a%b);}
set<int> g[2005];
bool used[2005],vis[2005];
int pa[2005];
pii dfs(int v,int f){
	pa[v]=f;
	int re0=v,re1=0;
	for(int u:g[v]){
		if(u==f||vis[u])continue;
		pii re=dfs(u,v);
		if(re.Y>re1)re0=re.X,re1=re.Y;
	}
	return {re0,re1+1};
}
void Solve(int n){
	int x=Query(0,1,2);
	if(x>=0&&x<=2){
		F(3){
			if(i==x)continue;
			g[i].insert(x);
			g[x].insert(i);
		}
	}
	else{
		F(3){
			g[i].insert(x);
			g[x].insert(i);
		}
	} 
	memres(used);
	F(3)used[i]=1;
	used[x]=1;
	Fl(i,3,n){
		if(used[i])continue;
		memres(vis);
		pii tmp=dfs(0,-1);
		int p1=tmp.X;
		tmp=dfs(p1,-1);
		int p2=tmp.X;
		int re;
		if(p1!=p2)re=Query(p1,p2,i);
		else re=p1;
		while(1){
			if(re==p1||re==p2){
				used[i]=1;
				g[re].insert(i);
				g[i].insert(re);
				break;
			}
			if(used[re]){
				int tp2=p2;
				while(tp2!=-1){
					vis[tp2]=1;
					tp2=pa[tp2]; 
				}
				vis[re]=0;
				tmp=dfs(re,-1);
				p1=tmp.X;
				tmp=dfs(p1,-1);
				p2=tmp.X;
				if(p1!=p2)re=Query(p1,p2,i);
				else re=p1;
			}
			else{
				int tp2=p2;
				vector<int> v;
				while(tp2!=-1){
					v.pb(tp2);
					tp2=pa[tp2];
				}
				int l=0,r=sz(v)-1;
				while(l+1<r){
					int mi=(l+r)/2;
					int t1=Query(v[l],v[mi],i);
					if(t1!=v[mi])r=mi;
					else l=mi;
				}
				assert(l+1==r);
				p1=v[l],p2=v[r];
				g[p1].erase(g[p1].find(p2));
				g[p2].erase(g[p2].find(p1));
				g[p1].insert(re);
				g[re].insert(p1);
				g[p2].insert(re);
				g[re].insert(p2);
				if(re!=i){
					g[re].insert(i);
					g[i].insert(re);
				} 
				used[i]=1;
				used[re]=1;
				break;
			}
		}
	}
	F(n){
		for(int j:g[i]){
			if(i<j)Bridge(i,j);
		}
	}
}
#ifdef LOCAL 
signed main(){
	int n;
	cin>>n;
	Solve(n);
	return 0;
}
#endif

• Subtask 1: 7 / 7
• Subtask 2: 10 / 10
• Subtask 3: 12 / 12
• Subtask 4: 71 / 71