You are given several queries. In the i-th query you are given a single positive integer ni. You are to represent ni as a sum of maximum possible number of composite summands and print this maximum number, or print -1, if there are no such splittings.
An integer greater than 1 is composite, if it is not prime, i.e. if it has positive divisors not equal to 1 and the integer itself.
InputThe first line contains single integer q (1 ≤ q ≤ 105) — the number of queries.
q lines follow. The (i + 1)-th line contains single integer ni (1 ≤ ni ≤ 109) — thei-th query.
For each query print the maximum possible number of summands in a valid splitting to composite summands, or -1, if there are no such splittings.
1 12
3
2 6 8
1 2
3 1 2 3
-1 -1 -1
12 = 4 + 4 + 4 = 4 + 8 = 6 + 6 = 12, but the first splitting has the maximum possible number of summands.
8 = 4 + 4, 6 can't be split into several composite summands.
1, 2, 3 are less than any composite number, so they do not have valid splittings.
代码
#include<cstdio>
#include<algorithm>
using namespace std;
int main()
{
int n,m;
while(scanf("%d",&n)!=EOF)
{
while(n--)
{
scanf("%d",&m);
if(m<=3||m==5||m==7||m==11)
printf("-1\n");
else
{
int ans=m/4;
if((m%4)%2)
ans--;
printf("%d\n",ans);
}
}
}
return 0;
}