78 lines
2.6 KiB
Java
78 lines
2.6 KiB
Java
import java.util.ArrayList;
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public class Heron {
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public static void main(String[] args) {
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ArrayList<int[]> list = new ArrayList<>();
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for (int c = 1; c <= 200; c++) {
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for (int b = 1; b <= c; b++) {
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for (int a = 1; a <= b; a++) {
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if (gcd(gcd(a, b), c) == 1 && isHeron(heronArea(a, b, c))){
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int area = (int) heronArea(a, b, c);
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list.add(new int[]{a, b, c, a + b + c, area});
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}
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}
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}
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}
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sort(list);
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System.out.printf("Number of primitive Heronian triangles with sides up "
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+ "to 200: %d\n\nFirst ten when ordered by increasing area, then"
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+ " perimeter:\nSides Perimeter Area", list.size());
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for (int i = 0; i < 10; i++) {
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System.out.printf("\n%d x %d x %d %d %d",
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list.get(i)[0], list.get(i)[1], list.get(i)[2],
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list.get(i)[3], list.get(i)[4]);
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}
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System.out.printf("\n\nArea = 210\nSides Perimeter Area");
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for (int i = 0; i < list.size(); i++) {
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if (list.get(i)[4] == 210)
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System.out.printf("\n%d x %d x %d %d %d",
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list.get(i)[0], list.get(i)[1], list.get(i)[2],
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list.get(i)[3], list.get(i)[4]);
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}
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}
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public static double heronArea(int a, int b, int c) {
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double s = (a + b + c) / 2f;
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return Math.sqrt(s * (s - a) * (s - b) * (s - c));
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}
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public static boolean isHeron(double h) {
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return h % 1 == 0 && h > 0;
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}
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public static int gcd(int a, int b) {
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int leftover = 1, dividend = a > b ? a : b, divisor = a > b ? b : a;
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while (leftover != 0) {
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leftover = dividend % divisor;
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if (leftover > 0) {
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dividend = divisor;
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divisor = leftover;
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}
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}
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return divisor;
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}
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public static void sort(ArrayList<int[]> list) {
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boolean swapped = true;
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int[] temp;
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while (swapped) {
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swapped = false;
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for (int i = 1; i < list.size(); i++) {
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if (list.get(i)[4] < list.get(i - 1)[4] ||
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list.get(i)[4] == list.get(i - 1)[4] &&
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list.get(i)[3] < list.get(i - 1)[3]) {
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temp = list.get(i);
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list.set(i, list.get(i - 1));
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list.set(i - 1, temp);
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swapped = true;
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}
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}
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}
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}
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}
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