Submission #1162217

#	Time	Username	Problem	Language	Result	Execution time	Memory
1162217		gustavo_d	Boxes with souvenirs (IOI15_boxes)	C++20	100 / 100	333 ms	196172 KiB

boxes

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

typedef long long ll;

const ll INF = 1e18;

ll delivery(int n, int k, int len, int p[]) {
    ll dpL[n+1]; dpL[0] = 0;
    ll dpR[n+1]; dpR[0] = 0;
    for (int i=0; i<=n; i++) {
        if (i != 0 and i <= k) dpL[i] = 2*p[i-1];
        else if (i != 0) dpL[i] = 2*p[i-1] + dpL[i-k];
    }
    for (int j=0; j<=n; j++) {
        if (j != 0 and j <= k) dpR[j] = 2*(len - p[n-j]);
        else if (j != 0) dpR[j] = 2LL*(len-p[n-j]) + dpR[j-k];
    }

    int pt = -1;
    for (int i=0; i<n; i++) {
        if (p[i] <= len / 2) pt = i;
        else break;
    }

    ll ans = dpL[pt+1] + dpR[n-pt-1];

    for (int i=max(0, pt - k - 5); i<=pt+1; i++) {
        int j = n - i - k;
        ll tmp = (i + j < n ? len : 0);
        tmp += dpL[i] + dpR[j];
        // cout << i << ' ' << j << ' ' << tmp << endl;
        ans = min(ans, tmp);
    }

    return ans;
}

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