47 lines
928 B
Java
47 lines
928 B
Java
package calculators;
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import java.util.InputMismatchException;
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import java.util.Scanner;
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class CombinationCalculator {
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private static Scanner scanner = new Scanner(System.in);
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private static int factorial(int n) {
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int res = 1;
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for (int i = 2; i <= n; i++) {
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res *= i;
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}
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return res;
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}
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private static int nCr(int n, int r) {
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return factorial(n) / (factorial(r) * factorial(n - r));
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}
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private static int intInput(String message) {
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int value = -1;
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while (value < 0) {
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try {
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System.out.print(message);
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value = scanner.nextInt();
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} catch (InputMismatchException e) {
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scanner.next();
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}
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}
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return value;
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}
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public static void main(String[] args) {
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// Take inputs
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int n = intInput("Please input the value for n: ");
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int r = intInput("Please input the value for r: ");
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scanner.close();
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// Calculate the result
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int result = nCr(n, r);
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System.out.println(result);
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}
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}
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