codeforces Ilya and Matrix

http://codeforces.com/contest/313/problem/C

 1 #include <cstdio>

 2 #include <cstring>

 3 #include <algorithm>

 4 using namespace std;

 5 long long a[3000000];

 6 

 7 int main()

 8 {

 9     int n;

10     scanf("%d",&n);

11     for(int i=0; i<n; i++)

12     {

13         scanf("%lld",&a[i]);

14     }

15     sort(a,a+n);

16     long long ans=0,ans1=0;

17     int k=1,j=0;

18     for(int i=n-1; i>=0; i--)

19     {

20         ans1+=a[i];

21         j++;

22         if(j==k)

23         {

24             ans+=ans1;

25             k=k*4;

26         }

27     }

28     printf("%lld\n",ans);

29     return 0;

30 }

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