Submission #559550

#	Time	Username	Problem	Language	Result	Execution time	Memory
559550		ahmet34	Finding Routers (IOI20_routers)	C++14	0 / 100	2 ms	1236 KiB

routers

#include <bits/stdc++.h>
#include "routers.h"
using namespace std;
 
using ll = long long;
using pii = pair<int, int>;
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()

const int INF = 2e9, N = 1e5+15, M = 998244353, LOG = 16;
const ll LINF = 1e18;

vector<int> bit;

void upd(int i, int x) {
	for(; i < N; i+=(i & -i)) bit[i] = min(bit[i], x);
}
int mn(int i) {
	int ret = INF;
	for(; i; i-=(i & -i)) ret = min(bit[i], ret);
	return ret;
}

vector<int> find_routers(int l, int n, int q) {
	vector<int> asked(l, -1);
	bit.assign(n+1, l-1);

	vector<int> ans {0};

	auto Ask = [&] (int x) {
		return asked[x] = (asked[x] >= 0 ? asked[x] : use_detector(x));
	};

	for(int i = 1; i < n; i++) 
	{
		int s = ans.back()+1, e = mn(i+1);
		//cout << i << ":  "<< s << ", " << e << '\n'; 
 		while(s < e) {
			int m = (s + e + 1) / 2;
			int cur = Ask(m);
			if(cur > i-1) {
				e = m-1;
				upd(N-1-cur, m);
				//cout << cur << " updated with " << m << '\n';
			}
			else s = m;
			q--;
		}
		ans.push_back(ans.back() + 2 * (s - ans.back()));
	}
	assert(q >= 0);
	return ans;
}

• Subtask 1: 0 / 16
• Subtask 2: 0 / 21
• Subtask 3: 0 / 23
• Subtask 4: 0 / 40