Submission #224471

#	Time	Username	Problem	Language	Result	Execution time	Memory
224471		DavidDamian	Boxes with souvenirs (IOI15_boxes)	C++11	50 / 100	2092 ms	8312 KiB

boxes

#include "boxes.h"
#include<bits/stdc++.h>
using namespace std;
///Partitions
///Determine the minimum distance that Adam has to travel to deliver all the souvenirs
///Subtask 4
///O(n^2)
///We have to partition the array into contiguous subsets of size k
///And one of size n%k
///We try all the possible rotations with the array (moving the start s)
///And the optimal has to be in one of that arrangements
///Since choosing not contiguous elements leads to bigger and overlapping subsets (we cannot leave gaps)
typedef long long ll;
int A[1000007];
int n;
int L;
ll sumRange(int s,int len) ///Return the cost of the range with start s and length len
{
    ll cost=0;
    int i=0;
    int id=0;
    while(i<len){
        id=(i+s)%n;
        if(i==0)
            cost+=(ll)min(A[id],L-A[id]);
        else{
            int dist=abs(A[id]-A[(id+n-1)%n]);
            cost+=(ll)min(dist,L-dist);
        }
        i++;
    }
    i--;
    id=(i+s)%n;
    cost+=(ll)min(A[id],L-A[id]);
    return cost;
}
long long delivery(int N, int k, int l, int p[]) {
    n=N;
    L=l;
    for(int i=0;i<n;i++){
        A[i]=p[i];
    }
    ll minimum=LLONG_MAX;
    for(int s=0;s<n;s++){ //For each possible start
        ll cost=0;
        if(n%k!=0) cost+=sumRange(s,n%k);
        for(int i=n%k;i<n;i+=k){ //We build the subsets and compute the cost of each one
            cost+=sumRange((s+i)%n,k);
        }
        minimum=min(minimum,cost);
    }
    return minimum;
}

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