HDU 5310 Souvenir

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=5310

[align=left]Problem Description[/align]
Today is the 1st anniversary of BestCoder. Soda, the contest manager, wants to buy a souvenir for each contestant. You can buy the souvenir one by one or set by set in the shop. The price for a souvenir is
p


yuan and the price for a set of souvenirs if q


yuan. There's m


souvenirs in one set.

There's n


contestants in the contest today. Soda wants to know the minimum cost needed to buy a souvenir for each contestant.

[align=left]Input[/align]
There are multiple test cases. The first line of input contains an integer
T


(1≤T≤10

5

)

,
indicating the number of test cases. For each test case:

There's a line containing 4 integers n,m,p,q


(1≤n,m,p,q≤10

4

)

.

[align=left]Output[/align]
For each test case, output the minimum cost needed.

[align=left]Sample Input[/align]

2
1 2 2 1
1 2 3 4

[align=left]Sample Output[/align]

1
3

Hint
For the first case, Soda can use 1 yuan to buy a set of 2 souvenirs.
For the second case, Soda can use 3 yuan to buy a souvenir.

#include<iostream>
using namespace std;
int main()
{
//	freopen("E:\\in.txt","r",stdin);
int T;
cin>>T;
while(T--){
bool flag=false;
int n,m,p,q;
int cost=0;
cin>>n>>m>>p>>q;
if(m*p>q)flag=true;	//set is cheaper
while(n>=m){
if(flag){
n-=m;
cost+=q;
}
else{
n-=1;
cost+=p;
}
}
if(n){	//rest need to buy
if(n*p>q)
cost+=q;
else
cost+=p*n;
}
cout<<cost<<endl;
}
return 0;
}