Submission #381094

#	Time	Username	Problem	Language	Result	Execution time	Memory
381094		BlancaHM	Finding Routers (IOI20_routers)	C++14	100 / 100	3 ms	620 KiB

routers

#include <iostream>
#include <vector>
#include <unordered_map>
#include "routers.h"
using namespace std;

vector<int> find_routers(int l, int n, int q) {
	vector<int> positions(n, -1);
	// Vamos buscando los routers uno a uno
	positions[0] = 0;
	int lo, hi, mid, k;
	unordered_map<int, int> calls;
	calls.reserve(4096);
	calls[0] = 0;
	calls[1] = 0;
	vector<int> low(n, 0), high(n, l);
	for (int i = 1; i < n; i++) {
		lo = max(positions[i-1], low[i-1]);
		hi = high[i];
		k = lo;
		while(lo <= hi) {
			mid = lo + (hi-lo)/2;
			if (calls.find(mid) == calls.end()) {
				calls[mid] = use_detector(mid);
				for (int j = i; j <= calls[mid]; j++)
					high[j] = min(high[j], mid);
				low[calls[mid]+1] = max(low[calls[mid]+1], mid);
			}
			if (calls[mid] < i) {
				k = mid;
				lo = mid+1;
			} else hi = mid-1;
		}
		positions[i] = positions[i-1] + 2*(k - positions[i-1]);
	}
	return positions;
}

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