Submission #1034517

#	Time	Username	Problem	Language	Result	Execution time	Memory
1034517		fv3	Boxes with souvenirs (IOI15_boxes)	C++14	100 / 100	694 ms	372060 KiB

boxes

#include "boxes.h"

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

const ll INF = 1ll << 60;

ll delivery(int N_, int K_, int L_, int p[])
{
    ll L = L_; ll N = N_; ll K = K_;

    vector<ll> v(N);
    for (int i = 0; i < N; i++)
        v[i] = p[i];
    sort(v.begin(), v.end());

    // Subtask 5: K <= 3000
    // Solve with Dynamic Programming

    // Let DP_r[i] be the minimum time to deliver the first i
    // packages and go back to start while only going right

    // Let DP_l[i] be the minimum time to deliver the last i
    // packages and go back to start while only going left

    // Find the optimal place to stop going right 
    vector<ll> DP_r(N + 1, INF), DP_l(N + 1, INF);
    DP_r[0] = 0; DP_l[N] = 0;

    for (int i = 1; i <= N; i++)
    {
        DP_r[i] = min(DP_r[max(0ll, i - K)] + v[i - 1] * 2, DP_r[max(0ll, i - K)] + L);
    }

    for (int i = N-1; i >= 0; i--)
    {
        DP_l[i] = min(DP_l[min(i+K, N)] + (L - v[i]) * 2, DP_l[min(i+K, N)] + L);
    }

    

    ll res = INF;
    for (int i = 0; i <= N; i++)
        res = min(res, DP_r[i] + DP_l[i]);

    return res;
}

Compilation message (stderr)

boxes.cpp: In function 'll delivery(int, int, int, int*)':
boxes.cpp:36:19: warning: conversion from 'll' {aka 'long long int'} to 'int' may change value [-Wconversion]
   36 |     for (int i = N-1; i >= 0; i--)
      |                  ~^~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 15 / 15
• Subtask 5: 20 / 20
• Subtask 6: 30 / 30