杨辉三角

 

 

 

import java.util.Scanner;

public class Triangle {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        int n = -1;
        while (cin.hasNext()) {
            n = cin.nextInt();
            getTriangle(n);
        }
    }

    // 杨辉三角
    public static void getTriangle(int n) {
        int[][] arr = new int[n][n];
        for (int i = 0; i < n; i++) {
            arr[i][0] = 1;
            arr[i][i] = 1;

        }
        // 下一行的数由上一行的两相邻数的和
        for (int i = 1; i < n - 1; i++) {
            for (int j = 0; j < i; j++) {
                arr[i + 1][j + 1] = arr[i][j] + arr[i][j + 1];
            }
        }
        // 上一行的两个相邻的数和为下一行的数
        for (int i = 2; i < n; i++) {
            for (int j = 1; j < i; j++) {
                arr[i][j] = arr[i - 1][j - 1] + arr[i - 1][j];
            }
        }
        for (int i = 0; i < n; i++) {
            for (int j = 0; j <= i; j++) {
                System.out.print(arr[i][j] + " ");
            }
            System.out.println();
        }
    }
}