Submission #1311097

#	Time	Username	Problem	Language	Result	Execution time	Memory
1311097		math_rabbit_1028	Shortcut (IOI16_shortcut)	C++20	0 / 100	1 ms	344 KiB

shortcut

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

int n, c;
vector<int> l, d;
vector<long long> sum;
vector<int> ord, idx;
vector<pair<long long, long long>> spd, smd;

bool check(long long lim) {
    pair<long long, long long> xpy = {-1e18, 1e18}, xmy = {-1e18, 1e18};
    int q = 0;
    for (int p = 0; p < n; p++) {
        int i = ord[p];
        while (q < n && d[i] + d[idx[q]] + sum[idx[q]] - sum[i] <= lim) q++;
        if (q == n) break;
        // xpy.first <- sum[i] + sum[j] - lim + c + d[i] + d[j] (max)
        // xpy.second <- sum[i] + sum[j] + lim - c - d[i] - d[j] (min)
        // xmy.first <- sum[i] - sum[j] - lim + c + d[i] + d[j] (max)
        // xmy.second <- sum[i] - sum[j] + lim - c - d[i] - d[j] (min)
        xpy.first = max(xpy.first, sum[i] - lim + c + d[i] + spd[q].second);
        xpy.second = min(xpy.second, sum[i] + lim - c - d[i] + smd[q].first);
        xmy.first = max(xmy.first, sum[i] - lim + c + d[i] - smd[q].first);
        xmy.second = min(xmy.second, sum[i] + lim - c - d[i] - spd[q].second);
    }
    for (int p = 0; p < n; p++) {
        for (int q = p + 1; q < n; q++) {
            if (xpy.first <= sum[p] + sum[q] && sum[p] + sum[q] <= xpy.second) {
                if (xmy.first <= sum[p] - sum[q] && sum[p] - sum[q] <= xmy.second) {
                    return true;
                }
            }
        }
    }
    return false;
}

long long find_shortcut(int _n, vector<int> _l, vector<int> _d, int _c) {
    n = _n;
    l = _l;
    d = _d;
    c = _c;
    sum.resize(n);
    sum[0] = 0;
    for (int i = 1; i < n; i++) {
        sum[i] = sum[i-1] + l[i-1];
    }
    idx.resize(n);
    for (int i = 0; i < n; i++) idx[i] = i;
    sort(idx.begin(), idx.end(), [](int a, int b) {
        return sum[a] + d[a] < sum[b] + d[b];
    });
    ord.resize(n);
    for (int i = 0; i < n; i++) ord[i] = i;
    sort(ord.begin(), ord.end(), [](int a, int b) {
        return sum[a] - d[a] < sum[b] - d[b];
    });
    spd.resize(n);
    for (int p = n - 1; p >= 0; p--) {
        int j = idx[p];
        if (p == n-1) spd[p] = {sum[j] + d[j], sum[j] + d[j]};
        else {
            spd[p].first = min(spd[p+1].first, sum[j] + d[j]);
            spd[p].second = max(spd[p+1].second, sum[j] + d[j]);
        }
    }
    smd.resize(n);
    for (int p = n - 1; p >= 0; p--) {
        int j = idx[p];
        if (p == n-1) smd[p] = {sum[j] - d[j], sum[j] - d[j]};
        else {
            smd[p].first = min(smd[p+1].first, sum[j] - d[j]);
            smd[p].second = max(smd[p+1].second, sum[j] - d[j]);
        }
    }

    long long st = 1, ed = 1e18;
    while (st < ed) {
        long long mid = (st + ed) / 2;
        if (check(mid)) ed = mid;
        else st = mid + 1;
    }
    
    return st;
}

Compilation message (stderr)

shortcut.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~
shortcut_c.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~

• Subtask 1: 0 / 9
• Subtask 2: 0 / 14
• Subtask 3: 0 / 8
• Subtask 4: 0 / 7
• Subtask 5: 0 / 33
• Subtask 6: 0 / 22
• Subtask 7: 0 / 4
• Subtask 8: 0 / 3