模拟：顺时针打印二维数组
核心思路：定义4个变量分别储存矩阵的四个顶点的横坐标的值，然后根据这个值反复归纳4个顶点的关系。然后把4个顶点“收缩”，进而完成顺时针打印矩阵的全部内容。
public class Main {
//创建StringBuilder对象ans储存结果
static StringBuilder ans = new StringBuilder("");
public static void main(String[] args) {
//测试用例
int[][] arr = new int[][]{
{
1, 2, 3, 4, 9},
{
5, 6, 7, 8, 22},
{
9, 10, 11, 12, 85},
{
13, 14, 15, 16, 66},
{
8, 14, 75, 56, 68},
};
printTwoDirectionsArrayByClockwise(arr);;
System.out.println(ans);
}
private static void printTwoDirectionsArrayByClockwise(int[][] arr) {
int index = 0;
int a,b,c,d;
do {
//取4个顶点的行坐标
a = index;
b = arr[0].length - 1 - index;
c = arr.length - 1 - index;
d = index;
//打印第一行
int upRow = a;
while (upRow <= b) {
ans.append(arr[a][upRow++]).append(" ");
//System.out.print(arr[a][upRow++] + " ");
}
//打印右边下面的一行
int dowCol = a;
dowCol++;
while (dowCol <= c) {
ans.append(arr[dowCol++][c]).append(" ");
//System.out.print(arr[dowCol++][c] + " ");
}
//打印下面到左边的一行
int downRow = c;
downRow--;
while (downRow >= d) {
ans.append(arr[c][downRow--]).append(" ");
//System.out.print(arr[c][downRow--] + " ");
}
//打印下面的到上面的一行
int upCol = c;
upCol--;
while (upCol > a) {
ans.append(arr[upCol--][d]).append(" ");
//System.out.print(arr[upCol--][d] + " ");
}
index++;
} while (a <= b && d < c);
}
}