Submission #813111

#	Time	Username	Problem	Language	Result	Execution time	Memory
813111		Kerim	Boxes with souvenirs (IOI15_boxes)	C++17	50 / 100	37 ms	17788 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[]) {
    vector<int> arr(n+2);
    arr[n+1] = l;
    for (int i = 1; i <= n; i++)
        arr[i] = p[i-1];
    ll answer = 0;
    if (k == 1){//subtask1
        for (int i = 1; i <= n; i++)
            answer += 2LL * min(arr[i], l - arr[i]);
    }
    else 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){
        vector<ll> pref(n+2), suf(n+2);
        answer = f(n, k) * 1LL * l;
        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];
        }
        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]));
            }
    }
    return answer;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 15 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30