Submission #796917

#	Time	Username	Problem	Language	Result	Execution time	Memory
796917		yikis44762	Rail (IOI14_rail)	C++17	100 / 100	133 ms	640 KiB

rail

#include<bits/stdc++.h>
using namespace std;
 
#define REP(i, n) for(int i = 0; i < n; i++)
#define FOR(i, a, b) for(int i = a; i <= b; i++)
 
#include "rail.h"
 
void findLocation(int N, int first, int location[], int stype[]) {
	auto fix = [&](int i, int pos, int type) {
		location[i] = pos;
		stype[i] = type;
	};
	REP(i, N) fix(i, -1, -1);
 
	fix(0, first, 1);
	vector<pair<int, int>> stations;
	FOR(i, 1, N - 1)
		stations.emplace_back(getDistance(0, i), i);	
 
	sort(stations.begin(), stations.end());
 
	int L = 0, R = stations[0].second;
	fix(R, first + stations[0].first, 2);
	stations.erase(stations.begin());
 
	for(auto &[d, i] : stations) {
		int a = getDistance(L, i);
		int b = getDistance(R, i);
 
		{ // [)]
			bool ok = false;
			int pos = location[L] + a;
			REP(j, N) {
				if(stype[j] == 1) {
					if(location[R] + pos - 2 * location[j] == b)
						ok = true;
				}
			}
			if(ok) {
				fix(i, pos, 2);
				if(location[R] < pos) R = i;
				continue;
			}
		}
		{ // (
			int pos = location[R] - b;
			bool ok = false;
			REP(j, N) {
				if(stype[j] == 2) {
					if(location[j] * 2 - pos - location[0] == d)
						ok = true;
				}
			}
			if(ok) {
				fix(i, pos, 1);
				if(pos < location[L]) L = i;
				continue;
			}
		}
		{ // [])
			int pos = location[L] + a;
			fix(i, pos, 2);
			R = i;
		}
	}
}

• Subtask 1: 8 / 8
• Subtask 2: 22 / 22
• Subtask 3: 26 / 26
• Subtask 4: 44 / 44