Table of Contents

ExplanationImplementation

Official Editorial

Explanation

We can find the total cost of ww bananas by calculating the sum of numbers from 1−W1 - W and multiplying by the price of the first banana, kk.

Now, we can just compare how much money is needed to buy the bananas.

Implementation

Time Complexity: O(1)\mathcal{O}(1)

Python

first, money, num = map(int, input().split())


cost = num * (num + 1) // 2
cost *= first


print(max(0, cost - money))

C++

#include <iostream>
using namespace std;


int main() {
	int first, num;
	long long money;
	cin >> first >> money >> num;


	int cost = num * (num + 1) / 2;
	cost *= first;


	cout << (max(0, cost - money));
}

Java

import java.io.*;
import java.util.*;


public class SoldierBananas {
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int first = input.nextInt();
		long money = input.nextInt();
		int num = input.nextInt();

Join the USACO Forum!

Stuck on a problem, or don't understand a module? Join the USACO Forum and get help from other competitive programmers!

Join Forum