cf B Inna and Candy Boxes

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 #define ll long long
 5 #define maxn 100100
 6 using namespace std;
 7 
 8 int n;
 9 ll a[maxn],b[maxn];
10 
11 int main()
12 {
13     while(scanf("%d",&n)!=EOF)
14     {
15         memset(a,0,sizeof(a));
16         memset(b,0,sizeof(b));
17         for(int i=1; i<=n; i++)
18         {
19             scanf("%lld",&a[i]);
20         }
21         for(int i=1; i<=n; i++)
22         {
23             scanf("%lld",&b[i]);
24         }
25         ll ans=0;
26         for(int i=1; i<=n; i++)
27         {
28             if(b[i]==1)
29             {
30                 ans--;
31                 continue;
32             }
33             if(b[i]-a[i]>a[i])
34             {
35                 ans--;
36                 continue;
37             }
38             if(b[i]%2==0)
39                 ans+=(ll)((ll)(b[i]/2)*(ll)(b[i]/2));
40             else
41                 ans+=(ll)((ll)(b[i]/2)*(ll)(b[i]/2+1));
42         }
43         printf("%lld\n",ans);
44     }
45     return 0;
46 }