Submission #813128

#	Time	Username	Problem	Language	Result	Execution time	Memory
813128		Kerim	Boxes with souvenirs (IOI15_boxes)	C++17	100 / 100	530 ms	333068 KiB

boxes

#include "boxes.h"
#include "bits/stdc++.h"

using namespace std;
#define ll long long

int f(int n, int k){
    return (n+k-1) / k;
}
long long delivery(int n, int k, int l, int p[]) {
    ll answer = f(n, k) * 1LL * l;
    vector<int> arr(n+2);
    arr[n+1] = l;
    for (int i = 1; i <= n; i++)
        arr[i] = p[i-1];
    vector<ll> pref(n+2), suf(n+2);
    for (int i = 1; i <= n; i++){
        pref[i] = arr[i];
        if (i >= k)
            pref[i] += pref[i-k];
    }
    for (int i = n; i >= 1; i--){
        suf[i] = l - arr[i];
        if (i + k <= n)
            suf[i] += suf[i+k];
    }
    if(k == n){//subtask2
        answer = l;
        for (int i = 0; i + 1 <= n + 1; i++)
            answer = min(answer, 2LL * (arr[i] + l - arr[i+1]));
    }
    else if(n <= 1000){
        for (int i = 0; i <= n; i++)
            for (int j = i+1; j <= n+1; j++){
                int c = f(j-i-1, k);
                answer = min(answer, c*1LL*l + 2*(pref[i] + suf[j]));
            }
    }
    else{//small k
        for (int i = 0; i <= n; i++){
            for (int c = 0; c <= min(1, (n-i)/k); c++){
                int j = c*1LL*k+1+i;
                answer = min(answer, c*1LL*l + 2*(pref[i] + suf[j]));
            }
        }
    }
    return answer;
}

Compilation message (stderr)

boxes.cpp: In function 'long long int delivery(int, int, int, int*)':
boxes.cpp:42:34: warning: conversion from 'long long int' to 'int' may change value [-Wconversion]
   42 |                 int j = c*1LL*k+1+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