Submission #556562

#	Time	Username	Problem	Language	Result	Execution time	Memory
556562		Jomnoi	Rail (IOI14_rail)	C++17	100 / 100	124 ms	98892 KiB

rail

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

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

int min_dist, firstD, latestC, latestD, flip_pos;
int dist[MAX_N][MAX_N], idx[MAX_N];
set <int> C, D;

int ask(int i, int j) {
    if(dist[i][j] != -1) {
        return dist[i][j];
    }
    if(i == j) {
        return dist[i][j] = 0;
    }
    return dist[i][j] = dist[j][i] = getDistance(i, j);
}

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

    location[0] = first;
    stype[0] = 1;

    min_dist = INF;
    for(int i = 1; i < N; i++) {
        if(min_dist > ask(0, i)) {
            min_dist = ask(0, i);
            firstD = i;
        }
    }

    location[firstD] = location[0] + ask(0, firstD);
    stype[firstD] = 2;

    C.insert(location[0]);
    D.insert(location[firstD]);
    latestC = 0;
    latestD = firstD;

    for(int i = 1; i < N; i++) {
        if(i != firstD) {
            if(ask(firstD, i) < ask(firstD, 0) and ask(0, i) - ask(firstD, 0) == ask(firstD, i)) { // find all C type that locate between 0 and firstD
                location[i] = location[firstD] - ask(firstD, i);
                stype[i] = 1;
                C.insert(location[i]);
            }
        }
    }

    sort(idx, idx + N, [&](const int &a, const int &b) {
        return ask(0, a) < ask(0, b);
    });

    for(int i = 0; i < N; i++) {
        if(stype[idx[i]] != 0) {
            continue;
        }

        if(ask(0, idx[i]) - ask(0, firstD) < ask(idx[i], firstD)) { // it is on the right of firstD
            location[idx[i]] = location[latestD] - ask(idx[i], latestD);
            flip_pos = *D.upper_bound(location[idx[i]]);
            if(ask(0, idx[i]) == 2 * flip_pos - location[idx[i]] - location[0]) {
                stype[idx[i]] = 1;
                C.insert(location[idx[i]]);
            }
            else {
                location[idx[i]] = location[0] + ask(0, idx[i]);
                stype[idx[i]] = 2;
                D.insert(location[idx[i]]);
                latestD = idx[i];
            }
        }
        else { // it is on the left of 0
            location[idx[i]] = location[latestC] + ask(idx[i], latestC);
            flip_pos = *prev(C.upper_bound(location[idx[i]]));
            if(ask(firstD, idx[i]) == location[firstD] + location[idx[i]] - 2 * flip_pos) {
                stype[idx[i]] = 2;
                D.insert(location[idx[i]]);
            }
            else {
                location[idx[i]] = location[firstD] - ask(firstD, idx[i]);
                stype[idx[i]] = 1;
                C.insert(location[idx[i]]);
                latestC = idx[i];
            }
        }
    }
}

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