蛇形矩阵

import java.util.Scanner;

public class SnakeMatrix {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt(); //首先输入矩阵的维数
		int a[][] = new int[n][n]; //存储所有元素的二维数组 
		int count = 1; //计数器，每走一步加一

 //把二维数组从外到内一层一层剥开，按照上、右、下、左的顺序走
// 注意临界值条件,尤其是拐角别重叠覆盖
 
		for (int i = 0; i < n/2+1; i++) {
			//up
			for (int j = i; j < n-i; j++){
				a[i][j]= count++;
			}
			//right
			for (int j = i+1; j < n-i; j++){
				a[j][n-i-1]= count++;
			}
			//down
			for (int j = n-i-2; j >=i; j--){
				a[n-i-1][j]= count++;
			}
			//left
			for (int j = n-i-2; j >i; j--){
				a[j][i]= count++;
			}
		}
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < n; j++) {
				System.out.print(a[i][j]+"\t");//将上面的for循环产生的数，进行遍历输出
				if(j==n-1)//拐角处
				System.out.println();
			}
		}
	}

}