Submission #838235

#	Time	Username	Problem	Language	Result	Execution time	Memory
838235		pavement	Rail (IOI14_rail)	C++17	30 / 100	86 ms	98700 KiB

rail

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

#define pb push_back

int dist[5005][5005];

void findLocation(int N, int first, int location[], int stype[]) {
	vector<int> left, right;
	vector<vector<int> > dist(N, vector<int>(N));
	location[0] = first;
	stype[0] = 1;
	dist[0][0] = 0;
	for (int i = 1; i < N; i++) {
		dist[0][i] = getDistance(0, i);
	}
	int X = min_element(dist[0].begin() + 1, dist[0].end()) - dist[0].begin(), Y = 0;
	stype[X] = 2;
	location[X] = first + dist[0][X];
	for (int i = 0; i < N; i++) {
		if (i == 0 || i == X) {
			continue;
		}
		dist[X][i] = getDistance(X, i);
		if (dist[X][i] < dist[0][X]) {
			stype[i] = 1;
			location[i] = location[X] - dist[X][i];
			if (location[Y] > location[i]) {
				Y = i;
			}
		} else if (dist[0][X] + dist[X][i] == dist[0][i]) {
			// left side
			left.pb(i);
		} else {
			// right side
			right.pb(i);
		}
	}
	// handle left side
	if (!left.empty()) {
		map<int, int> processed;
		sort(left.begin(), left.end(), [&](const int &lhs, const int &rhs) {
			return dist[X][lhs] < dist[X][rhs];
		});
		int cl = left[0];
		location[cl] = location[X] - dist[X][cl];
		stype[cl] = 1;
		processed[location[cl]] = stype[cl];
		for (int i = 1; i < (int)left.size(); i++) {
			int cur = left[i];
			int tmp = getDistance(cl, cur);
			int v = dist[X][cl] + tmp - dist[X][cur];
			assert(v % 2 == 0);
			if (processed.find(location[cl] + v / 2) == processed.end() || processed[location[cl] + v / 2] == 2) {
				location[cur] = location[cl] - (tmp - v);
				stype[cur] = 1;
				cl = cur;
			} else {
				location[cur] = location[cl] + tmp;
				stype[cur] = 2;
			}
			processed[location[cur]] = stype[cur];
		}
	}
	// handle right side
	if (!right.empty()) {
		for (int i = 0; i < N; i++) {
			dist[Y][i] = dist[0][i] - (location[Y] - location[0]);
		}
		map<int, int> processed;
		sort(right.begin(), right.end(), [&](const int &lhs, const int &rhs) {
			return dist[Y][lhs] < dist[Y][rhs];
		});
		int cl = right[0];
		location[cl] = location[Y] + dist[Y][cl];
		stype[cl] = 2;
		processed[location[cl]] = stype[cl];
		for (int i = 1; i < (int)right.size(); i++) {
			int cur = right[i];
			int tmp = getDistance(cl, cur);
			int v = dist[Y][cl] + tmp - dist[Y][cur];
			assert(v % 2 == 0);
			if (processed.find(location[cl] - v / 2) == processed.end() || processed[location[cl] - v / 2] == 2) {
				location[cur] = location[cl] + (tmp - v);
				stype[cur] = 2;
				cl = cur;
			} else {
				location[cur] = location[cl] - tmp;
				stype[cur] = 1;
			}
			processed[location[cur]] = stype[cur];
		}
	}
}

• Subtask 1: 8 / 8
• Subtask 2: 22 / 22
• Subtask 3: 0 / 26
• Subtask 4: 0 / 44