Submission #581970

#	Time	Username	Problem	Language	Result	Execution time	Memory
581970		8e7	Highway Tolls (IOI18_highway)	C++17	51 / 100	444 ms	15260 KiB

highway

#include "highway.h"
//Challenge: Accepted
#include <bits/stdc++.h>
using namespace std;
#ifdef zisk
void debug(){cout << endl;}
template<class T, class ... U> void debug(T a, U ... b){cout << a << " ", debug(b...);}
template<class T> void pary(T l, T r) {
	while (l != r) cout << *l << " ", l++;
	cout << endl;
}
#else
#define debug(...) 0
#define pary(...) 0
#endif
#define ll long long
#define maxn 100005
#define pii pair<int, int>
#define ff first
#define ss second
#define io ios_base::sync_with_stdio(0);cin.tie(0);
vector<pii> adj[maxn];
ll mind;
vector<int> tmp;
int ord[maxn];
void dfs(int n, int par, int &cur, int lim) {
	ord[cur++] = n;	
	if (cur > lim) return;
	for (auto [v, id]:adj[n]) {
		if (v != par && cur + 1 <= lim) {
			tmp[id] = 0;
			dfs(v, n, cur, lim);
			if (cur > lim) return;
		} 
	}
}
int getind(int n, int root) {
	int low = 0, up = n;
	tmp.resize(n - 1, 0);	

	dfs(root, 0,low, 1<<30); 
	low = 0;
	while (low < up - 1) {
		int mid = (low + up) / 2;
		for (int i = 0;i < n - 1;i++) tmp[i] = 1;
		int ini = 0;
		dfs(root, 0, ini, mid); 

		//debug(low, mid, up);
		//pary(tmp.begin(), tmp.end());
		ll val = ask(tmp);
		if (val == mind) {
			up = mid;	
		} else {
			low = mid;
		}
	}
	//debug(up, ord[up-1]);
	return ord[up-1];
}
void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
	int M = U.size();
	vector<int> ini(M, 0);
	mind = ask(ini);
	for (int i = 0;i < M;i++) {
		adj[U[i]].push_back({V[i], i});
		adj[V[i]].push_back({U[i], i});
	}
	int s = getind(N, 0);
	int t = getind(N, s);
	debug(s, t);
	answer(s, t);
}
/*
4 3 5 8 1 3
0 1
0 2
1 3
*/

Compilation message (stderr)

highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:13:20: warning: statement has no effect [-Wunused-value]
   13 | #define debug(...) 0
      |                    ^
highway.cpp:71:2: note: in expansion of macro 'debug'
   71 |  debug(s, t);
      |  ^~~~~

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