Submission #501644

#	Time	Username	Problem	Language	Result	Execution time	Memory
501644		blue	Shortcut (IOI16_shortcut)	C++17	71 / 100	2061 ms	2092 KiB

shortcut

#include "shortcut.h"
#include <vector>
#include <iostream>
using namespace std;

using ll = long long;
using vll = vector<ll>;

const ll INF = 1'000'000'000'000'000'000LL;

ll find_shortcut(int n, vector<int> track_len, vector<int> d, int c)
{
    vll x(n, 0);
    for(int i = 1; i < n; i++) x[i] = x[i-1] + track_len[i-1];

    ll lo = 1;
    ll hi = 1'000'000'000'000'000'000LL;

    vll y(n, 0);
    for(int i = 0; i < n; i++) y[i] = d[i];

    ll l = c;

    while(lo != hi)
    {
        ll k = (lo+hi)/2;

        ll sum_lo = -INF;
        ll sum_hi = INF;

        ll diff_lo = -INF;
        ll diff_hi = INF;

        for(int i = 0; i < n; i++)
        {
            for(int j = i+1; j < n; j++)
            {
                if(y[i] + y[j] + x[j] - x[i] <= k) continue;

                sum_lo = max(sum_lo, (x[i] + y[i]) + (x[j] + y[j]) + l - k);
                sum_hi = min(sum_hi, (x[i] - y[i]) + (x[j] - y[j]) + k - l);

                diff_hi = min(diff_hi, -(x[i] + y[i]) + (x[j] - y[j]) + k - l);
                diff_lo = max(diff_lo, -(x[i] - y[i]) + (x[j] + y[j]) + l - k);
            }
        }

        bool works = 0;

        for(int i = 0; i < n; i++)
        {
            for(int j = i+1; j < n; j++)
            {
                if(sum_lo <= x[i] + x[j] && x[i] + x[j] <= sum_hi)
                {
                    if(diff_lo <= x[j] - x[i] && x[j] - x[i] <= diff_hi)
                    {
                        works = 1;
                    }
                }
            }
        }

        if(works) hi = k;
        else lo = k+1;
    }

    return lo;
}

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