java杨辉三角简单实现

迭代实现

public class Yang3 {

    public static void main(String[] args) {
        compute(9);
    }

    public static void compute(int level) {
        int[] a = new int[level + 1];
        a[0] = 1;
        showRow(a, 1);

        for (int i = 1; i < a.length; i++) {
            for (int j = i; j > 0; j--) {
                a[j] += a[j - 1];
            }
            showRow(a, i + 1);
        }
    }

    private static void showRow(int[] a, int length) {
        for (int i = 0; i < length; i++) {
            System.out.print(a[i] + "\t");
        }
        System.out.println();
    }
}

递归实现

public class Yang4 {

    public static void main(String[] args) {
        compute(9);
    }

    public static void compute(int level) {
        for (int n = 0; n <= level; n++) {
            for (int c = 0; c <= n; c++) {
                System.out.print(compute(n, c) + "\t");
            }
            System.out.println();
        }
    }

    public static int compute(int n, int c) {
        if (c == n || c == 0)
            return 1;
        return compute(n - 1, c) + compute(n - 1, c - 1);
    }
}