제출 #349121

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
349121		amunduzbaev	통행료 (IOI18_highway)	C++14	39 / 100	328 ms	65580 KiB

highway

/*
Say hello to my algoeithmic goose

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*/

#include "highway.h"
#include <bits/stdc++.h>
#ifndef EVAL
#include "grader.cpp"
#endif
using namespace std;
 
#define pb push_back
#define sz(x) (int)x.size()
#define ff first
#define ss second
#define vv vector 
typedef pair<int, int> pii; 
#define ll long long

const int NN = 1e6+5;
vv<pii> edges[NN];
vv<pii> gg[NN];
vv<int> tr;
vv<int> tt;
int un[NN], used[NN], wh[NN], rr, dd[NN], on[NN], l, r;
ll dis; 

void dfs(int u, int p, int d = 0){
	if(d == dis) tt.pb(u);
	
	dd[u] = d;
	for(auto x : edges[u]){
		if(x.ff == p) continue;
		on[x.ff] = x.ss;
		dfs(x.ff, u, d+1);
	}
}
 
void find_pair(int N, vector<int> U, vector<int> V, int A, int B) {
	//~ cout<<"\n";
	for(int i=0;i<sz(V);i++){
		gg[V[i]].pb({U[i], i});
		gg[U[i]].pb({V[i], i});
	}
	
	int mm = sz(V);
	tr.resize(mm, 0);
	dis = ask(tr)/A;
	
	l = 0, r = mm-1;
	while(l+1 < r){
		//~ cout<<l<<" "<<r<<"\n";
		int m = (l + r+1)>>1;
		for(int i=l;i<=m;i++) tr[i] = 1;
		
		ll res = ask(tr);
		
		for(int i=l;i<=m;i++) tr[i] = 0;
		
		if(res > dis*A) r = m;
		else l = m+1;
	}
	
	tr[r] = 1;
	ll res = ask(tr);
	if(res > dis*A) l = r;
	tr[r] = 0;
	
	rr = V[l];
	queue<int> q;
	q.push(rr);
	used[rr] = 1;
	
	//~ cout<<rr<<"\n";
	
	while(!q.empty()){
		int cur = q.front(); q.pop();
		for(auto x : gg[cur]){
			if(used[x.ff]) continue;
			edges[cur].pb(x);
			edges[x.ff].pb({cur, x.ss});
			used[x.ff] = 1;
			q.push(x.ff);
		}
	}
	
	//~ cout<<"\n";
	//~ for(int i=0;i<N;i++){
		//~ for(auto x:edges[i]) cout<<i<<" "<<x.ff<<"\n";
	//~ }
	//~ cout<<"\n";
	queue<int> qq;
	qq.push(rr);
	memset(used, 0, sizeof used);
	un[rr] = 1, used[rr] = 1;
	int last = rr;
	wh[last] = 0;
 
	while(!qq.empty()){
		int cur = qq.front(); qq.pop();
		for(auto x : edges[cur]){
			if(used[x.ff]) continue;
			un[x.ff] = ++last;
			used[x.ff] = 1;
			wh[last] = x.ff;
			qq.push(x.ff);
		}
	}
	
	//~ for(int i=0;i<N;i++) cout<<un[i]<<" ";
	//~ cout<<"\n";
	
	l = 1, r = last;
	ll br = dis * B;
	while(l+1 < r){
		int m = (l + r)>>1;
		
		for(int i=1;i<=m;i++){
			for(auto x:edges[wh[i]]){
				if(un[x.ff] > m) continue;
				tr[x.ss] = 1;
			}
		}
		
		ll res = ask(tr);
		tr.assign(mm, 0);
		
		if(res < br) l = m+1;
		else r = m;
	}
	
	int m = l;
	for(int i=1;i<=m;i++){
		for(auto x:edges[wh[i]]){
			if(un[x.ff] > m) continue;
			tr[x.ss] = 1;
		}
	}
	
	res = ask(tr);
	tr.assign(mm, 0);
	
	if(res < br) l = r;
	
	rr = wh[l];
	//~ cout<<rr<<"\n";
	
	dfs(rr, -1, 0);
	
	l = 0, r = sz(tt)-1;
	
	while(l < r){
		int m = (l + r)>>1;
		tr.assign(mm, 0);
		for(int i=0;i<=m;i++) tr[on[tt[i]]] = 1;
		ll res = ask(tr);
		
		if(res > dis*A) r = m;
		else l = m+1;
	}
	//~ cout<<"\n"<<rr<<" "<<tt[l]<<"\n";
	answer(rr, tt[l]);
}
 
/*
 
7 6 1 2 0 4
0 1 
0 2 
0 3 
3 4 
2 6 
3 5 

8 10 1 2 1 5
0 1
0 2
1 3
2 3
2 4
3 5
4 5
6 7
7 2
6 4

11 16 1 2 3 8
0 1
1 2
0 3
1 4
1 5
2 6
2 7
7 8
3 4
4 5
5 6
6 7
5 9
9 10
10 6
10 7


*/
 
 

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