在Android Studio中计算组合

public class CombinationCalculator {

    // 计算阶乘
    private static long factorial(int n) {
        long result = 1;
        for (int i = 1; i <= n; i++) {
            result *= i;
        }
        return result;
    }

    // 计算组合数
    public static long combination(int n, int m) {
        if (m > n) {
            return 0;
        }
        return factorial(n) / (factorial(m) * factorial(n - m));
    }

    public static void main(String[] args) {
        int n = 5;
        int m = 2;
        long result = combination(n, m);
        System.out.println("C(" + n + ", " + m + ") = " + result);
    }
}

import java.math.BigInteger;

public class CombinationCalculator {

    // 计算阶乘
    private static BigInteger factorial(int n) {
        BigInteger result = BigInteger.ONE;
        for (int i = 1; i <= n; i++) {
            result = result.multiply(BigInteger.valueOf(i));
        }
        return result;
    }

    // 计算组合数
    public static BigInteger combination(int n, int m) {
        if (m > n) {
            return BigInteger.ZERO;
        }
        return factorial(n).divide(factorial(m).multiply(factorial(n - m)));
    }

    public static void main(String[] args) {
        int n = 50;
        int m = 25;
        BigInteger result = combination(n, m);
        System.out.println("C(" + n + ", " + m + ") = " + result);
    }
}