Submission #821567

#	Time	Username	Problem	Language	Result	Execution time	Memory
821567		Dan4Life	Highway Tolls (IOI18_highway)	C++17	0 / 100	161 ms	262144 KiB

highway

#include "highway.h"
#include <bits/stdc++.h>
using namespace std;
using vi = vector<int>;
#define pb push_back
#define sz(a) (int)a.size()
#define all(a) begin(a),end(a)
const int mxN = (int)2e5+10;
using ll = long long;
vector<pair<int,int>> adj[mxN];
int n, m, dist, dis[mxN];
vector<int> edges;

void dfs(int s, int p){
	if(p!=-1) dis[s] = dis[p]+1;
	else dis[s] = 0;
	for(auto [u,i] : adj[s]){	
		if(u!=p){
			dfs(u,s);
			if(dis[u]==dist) edges.pb(i);
		}
	}
}

void find_pair(int N, vi u, vi v, int A, int B) {
	n = N; m = sz(u); vi w(m,0);
	for(int i = 0; i < m; i++){
		int a = u[i], b = v[i];
		adj[a].pb({b,i}); adj[b].pb({a,i});
	}
	ll toll = ask(w);
	dist = toll/A; dfs(0,-1);
	int l = 0, r = m-1;
	while(l<r){
		int mid = (l+r)/2; fill(all(w),0);
		fill(begin(w),begin(w)+mid,1);
		if(ask(w)!=toll) r=mid;
		else l=mid+1;
	}
	int x = l; l = 0, r = m-1;
	while(l<r){
		int mid = (l+r+1)/2; fill(all(w),0);
		fill(begin(w)+mid,end(w),1);
		if(ask(w)!=toll) l=mid;
		else r=mid-1;
	}
	answer(x,l+1);
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 7
• Subtask 3: 0 / 6
• Subtask 4: 0 / 33
• Subtask 5: 0 / 18
• Subtask 6: 0 / 31