/*
* The sum of the squares of the first ten natural numbers is,
* 12 + 22 + ... + 102 = 385
* The square of the sum of the first ten natural numbers is,
* (1 + 2 + ... + 10)2 = 552 = 3025
* Hence the difference between the sum of the squares of
* the first ten natural numbers and the square of the sum is 3025 − 385 = 2640.
*
* Find the difference between the sum of
* the squares of the first one hundred natural numbers and the square of the sum.
*/
public class Problem6 {
int squareSum(int firstN) {
int sum = 0;
for (int i = 1; i <= firstN; i++) {
sum += i * i;
}
return sum;
}
int sumSquare(int firstN) {
return (int) Math.pow(firstN * (firstN + 1) / 2, 2);
}
int solve(int firstN) {
return sumSquare(firstN) - squareSum(firstN);
}
public static void main(String[] args) {
// 25164150
System.out.println(new Problem6().solve(100));
}
}
오늘 문제는 너무 쉬워서 한개 더 풀겠음