package ProjectEuler;

/**
 * Each new term in the Fibonacci sequence is generated by adding the previous two terms. By
 * starting with 1 and 2, the first 10 terms will be:
 *
 * <p>1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
 *
 * <p>By considering the terms in the Fibonacci sequence whose values do not exceed four million,
 * find the sum of the even-valued terms.
 *
 * <p>Link: https://projecteuler.net/problem=2
 */
public class Problem02 {
 public static void main(String[] args) {
 int[][] testNumbers = {
 {10, 10}, /* 2 + 8 == 10 */
 {15, 10}, /* 2 + 8 == 10 */
 {2, 2},
 {1, 0},
 {89, 44} /* 2 + 8 + 34 == 44 */
 };

 for (int[] ints : testNumbers) {
 assert solution1(ints[0]) == ints[1];
 }
 }

 private static int solution1(int n) {
 int sum = 0;
 int first = 1;
 int second = 2;
 while (second <= n) {
 if (second % 2 == 0) {
 sum += second;
 }
 int temp = first + second;
 first = second;
 second = temp;
 }
 return sum;
 }
}