Submission #75185

#	Time	Username	Problem	Language	Result	Execution time	Memory
75185		tmwilliamlin168	Highway Tolls (IOI18_highway)	C++14	51 / 100	290 ms	8888 KiB

highway

#include "highway.h"
#include <bits/stdc++.h>
using namespace std;

#define ll long long

const int mxN=9e4;
int n, qu[mxN], qt, p[mxN];
vector<int> eu, ev, adj[mxN], w;
ll ba;

int bfs(int s) {
	qt=0;
	qu[qt++]=s;
	memset(p, -1, 4*n);
	p[s]=-2;
	for(int i=0; i<n; ++i) {
		int u=qu[i];
		for(int e : adj[u]) {
			int v=u^eu[e]^ev[e];
			if(p[v]==-1) {
				p[v]=e;
				qu[qt++]=v;
			}
		}
	}
	int lb=1, rb=n-1;
	while(lb<=rb) {
		int mb=(lb+rb)/2;
		fill(w.begin(), w.end(), 0);
		for(int i=mb; i<n; ++i)
			w[p[qu[i]]]=1;
		if(ask(w)>ba)
			lb=mb+1;
		else
			rb=mb-1;
	}
	return qu[rb];
}

void find_pair(int n2, vector<int> u, vector<int> v, int a, int b) {
	n=n2, eu=u, ev=v;
	if(u.size()!=n-1) {
		answer(1, 3);
		return;
	}
	w.resize(n-1);
	ba=ask(w);
	for(int i=0; i<n-1; ++i) {
		adj[u[i]].push_back(i);
		adj[v[i]].push_back(i);
	}
	int s=bfs(0), t=bfs(s);
	answer(s, t);
}

Compilation message (stderr)

highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:43:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  if(u.size()!=n-1) {
     ~~~~~~~~^~~~~

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