Buy 2 Get 1 Free codechef solution in cpp

 

Buy 2 Get 1 Free Problem Code: SALE2Submit (Practice)

There is a sale going on in Chefland. For every 2$2$ items Chef pays for, he gets the third item for free (see sample explanations for more clarity).

It is given that the cost of 1$1$ item is X$X$ rupees. Find the minimum money required by Chef to buy at least N$N$ items.

Input Format

• First line will contain T$T$, number of test cases. Then the test cases follow.
• Each test case contains of a single line of input, two integers N$N$ and X$X$.

Output Format

For each test case, output the minimum money required by Chef to buy at least N$N$ items.

Constraints

• 1≤T≤1000$1\le T\le 1000$
• 1≤N,X≤1000$1\le N,X\le 1000$

Subtasks

• Subtask 1 (100 points): Original constraints.

Sample Input 1 

4
3 4
4 2
5 3
6 1

Sample Output 1 

8
6
12
4

Explanation

Test Case 1$1$: Chef wants 3$3$ items where the cost of each item is 4$4$ rupees. To minimise the expenditure, Chef can pay for 2$2$ items and get the third item for free. This way, the total money required is 4⋅2=8$4\cdot 2=8$ rupees.

Test Case 2$2$: To minimise the expenditure, Chef can do the following:

• Purchase 2$2$ items for 2⋅2=4$2\cdot 2=4$ rupees and get the third one free. Thus, the total number of items is 3$3$.
• Purchase 1$1$ item for 2⋅1=2$2\cdot 1=2$ rupees. Now Chef has total 4$4$ items.

Thus, the minimum money required to buy 4$4$ items is 4+2=6$4+2=6$ rupees.

Test Case 3$3$: To minimise the expenditure, Chef can do the following:

• Purchase 2$2$ items for 3⋅2=6$3\cdot 2=6$ rupees and get the third one free. Thus, the total number of items is 3$3$.
• Purchase 2$2$ items for 3⋅2=6$3\cdot 2=6$ rupees. Chef gets a third item for free. Now Chef has total 6$6$ items which is greater than his requirement of 5$5$ items.

Chef wanted to buy at least 5$5$ items. The minimum money required for that is 6+6=12$6+6=12$ rupees.

Test Case 4$4$: To minimise the expenditure, Chef can do the following:

• Purchase 2$2$ items for 1⋅2=2$1\cdot 2=2$ rupees and get the third one free. Thus, the total number of items is 3$3$.
• Purchase 2$2$ items for 1⋅2=2$1\cdot 2=2$ rupees and get the third one free.. Now Chef has total 6$6$ items.

Thus, the minimum money required to buy 6$6$ items is 2+2=4$2+2=4$ rupees.

solution

#include<iostream>
#include<vector>
#include<cmath>
#include<algorithm>
#include<climits>
#include<string>
using namespace std;

class solution
{
public:
	void solve()
	{
		int x, cnt , n, sum, total;
		cin >> x >> n;
		cnt = x / 3;
		sum = x * n;
		total = sum - (cnt * n);
		cout << total << "\n";
	}
};
int main()
{
	solution ss;

	int t;
	cin >> t;
	while (t--)
    {
		ss.solve();
	}

	return 0;
}