HDU 5310 Souvenir

Problem Description

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.

Input

There are multiple test cases. The first line of input contains an integer $T$ (1 \le T \le 10^5)(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 \le n, m, p, q \le 10^4)(1≤n,m,p,q≤10​4​​).

Output

For each test case, output the minimum cost needed.

Sample Input

21 2 2 11 2 3 4

Sample Output

13
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.
简单题
考虑三种情况即可
#include<cstdio>#include<cmath>#include<queue>#include<vector>#include<stack>#include<map>#include<string>#include<cstring>#include<algorithm>#include<iostream>using namespace std;typedef long long ll;const ll maxn = 100005;int T, n, m, p, q, ans;int main(){    cin >> T;    while (T--)    {        scanf("%d%d%d%d", &n, &m, &p, &q);        ans = n * p;        ans = min(ans, n / m * q + n % m * p);        ans = min(ans, (n + m - 1) / m * q);        printf("%d\n", ans);    }    return 0;}