reformat
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/*
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package ProjectEuler;
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The sequence of triangle numbers is generated by adding the natural numbers. So the 7th triangle number would be 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28.
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/**
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The first ten terms would be:
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* The sequence of triangle numbers is generated by adding the natural numbers.
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* So the 7th triangle number would be 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28.
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1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
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* The first ten terms would be:
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* <p>
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Let us list the factors of the first seven triangle numbers:
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* 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
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* <p>
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1: 1
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* Let us list the factors of the first seven triangle numbers:
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3: 1,3
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* <p>
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6: 1,2,3,6
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* 1: 1
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10: 1,2,5,10
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* 3: 1,3
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15: 1,3,5,15
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* 6: 1,2,3,6
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21: 1,3,7,21
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* 10: 1,2,5,10
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28: 1,2,4,7,14,28
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* 15: 1,3,5,15
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We can see that 28 is the first triangle number to have over five divisors.
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* 21: 1,3,7,21
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* 28: 1,2,4,7,14,28
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What is the value of the first triangle number to have over five hundred divisors?
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* We can see that 28 is the first triangle number to have over five divisors.
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* <p>
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* What is the value of the first triangle number to have over five hundred divisors?
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* <p>
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* link: https://projecteuler.net/problem=12
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*/
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*/
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public class Problem12 {
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public class Problem_12 {
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/**
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* Driver Code
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*/
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public static void main(String[] args) {
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assert solution1(500) == 76576500;
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}
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/* returns the nth triangle number; that is, the sum of all the natural numbers less than, or equal to, n */
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/* returns the nth triangle number; that is, the sum of all the natural numbers less than, or equal to, n */
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public static int triangleNumber(int n) {
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public static int triangleNumber(int n) {
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@ -28,15 +38,12 @@ public class Problem_12 {
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return sum;
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return sum;
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}
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}
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public static void main(String[] args) {
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public static int solution1(int number) {
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long start = System.currentTimeMillis(); // start the stopwatch
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int j = 0; // j represents the jth triangle number
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int j = 0; // j represents the jth triangle number
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int n = 0; // n represents the triangle number corresponding to j
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int n = 0; // n represents the triangle number corresponding to j
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int numberOfDivisors = 0; // number of divisors for triangle number n
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int numberOfDivisors = 0; // number of divisors for triangle number n
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while (numberOfDivisors <= 500) {
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while (numberOfDivisors <= number) {
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// resets numberOfDivisors because it's now checking a new triangle number
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// resets numberOfDivisors because it's now checking a new triangle number
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// and also sets n to be the next triangle number
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// and also sets n to be the next triangle number
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@ -54,10 +61,6 @@ public class Problem_12 {
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// so multiply it by 2 to include the other corresponding half
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// so multiply it by 2 to include the other corresponding half
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numberOfDivisors *= 2;
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numberOfDivisors *= 2;
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}
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}
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return n;
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long finish = System.currentTimeMillis(); // stop the stopwatch
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System.out.println(n);
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System.out.println("Time taken: " + (finish - start) + " milliseconds");
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}
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}
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}
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}
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