Submission #556286

#	Time	Username	Problem	Language	Result	Execution time	Memory
556286		Jomnoi	Rail (IOI14_rail)	C++17	8 / 100	90 ms	55000 KiB

rail

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

const int MAX_N = 5e3 + 10;
const int INF = 1e9 + 7;

int min_dist, firstD, latestC, latestD;
int dist[MAX_N][MAX_N];
vector <pair <int, int>> L, R;

void findLocation(int N, int first, int location[], int stype[]) {
    for(int i = 1; i < N; i++) {
        dist[0][i] = dist[i][0] = getDistance(0, i);
    }

    location[0] = first;
    stype[0] = 1;
    
    min_dist = INF;
    for(int i = 1; i < N; i++) {
        if(min_dist > dist[0][i]) {
            min_dist = dist[0][i];
            firstD = i;
        }
    }

    location[firstD] = first + min_dist;
    stype[firstD] = 2;

    for(int i = 1; i < N; i++) {
        if(i != firstD) {
            dist[firstD][i] = dist[i][firstD] = getDistance(firstD, i);
        }
    }

    for(int i = 1; i < N; i++) {
        if(i == firstD) {
            continue;
        }

        if(dist[firstD][i] < dist[0][i]) { // it is on the left of the station 0
            location[i] = location[firstD] - dist[firstD][i];
            stype[i] = 1;
            if(location[i] < first) {
                L.emplace_back(location[i], i);
            }
        }
        else { // it is on the right of the first station that is type D
            location[i] = first + dist[0][i];
            stype[i] = 2;
            R.emplace_back(location[i], i);
        }
    }

    sort(L.rbegin(), L.rend());
    sort(R.begin(), R.end());

    if(!R.empty()) {
        latestC = 0;
        latestD = R.front().second;
        location[latestD] = first + dist[0][latestD];
        stype[latestD] = 2;
        for(auto [distFrom0, idx] : R) {
            if(idx == latestD) {
                continue;
            }

            dist[idx][latestD] = dist[latestD][idx] = getDistance(latestD, idx);
            if(dist[latestD][idx] < dist[latestC][idx]) {
                location[idx] = location[latestD] - dist[latestD][idx];
                stype[idx] = 1;
                latestC = idx;
            }
            else {
                location[idx] = location[latestC] + dist[latestC][idx];
                stype[idx] = 2;
                latestD = idx;
            }
        }
    }
    if(!L.empty()) {
        latestC = L.front().second;
        latestD = firstD;
        location[latestC] = location[firstD] - dist[firstD][latestC];
        stype[latestC] = 1;
        for(auto [distFromFirstD, idx] : L) {
            if(idx == latestC) {
                continue;
            }

            dist[idx][latestC] = dist[latestC][idx] = getDistance(latestC, idx);
            if(dist[latestC][idx] < dist[latestD][idx]) {
                location[idx] = location[latestC] + dist[latestC][idx];
                stype[idx] = 1;
                latestC = idx;
            }
            else {
                location[idx] = location[latestD] - dist[latestD][idx];
                stype[idx] = 2;
                latestD = idx;
            }
        }
    }
}

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