顺时针打印矩阵

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剑指offer有一道关于顺时针打印矩阵的面试题，感觉挺有意思的，题意很简单，输入一个矩阵，顺时针打印每个数字。
例如输入以下矩阵
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
打印的结果是1 2 3 4 8 12 16 15 14 13 9 5 6 7 11 10 。本体的关键是要把握好边界条件，每次从左上角的开始打印。

package sxd.learn.java.questions;public class PrintMatrix {    private int r_upper_threshold;    private int c_upper_threshold;    private int r_lower_threshold;    private int c_lower_threshold;    public static void main(String[] args) {        new PrintMatrix().run();    }    public void run(){        int[][] matrix1 = {                {1, 2, 3, 4},                {5, 6, 7, 8},                {9, 10, 11, 12},                {13, 14, 15, 16}        };        int[][] matrix2 = {                {1, 2, 3, 4},                {2, 3, 4, 5},                {5, 6, 7, 8},        };        int[][] matrix3 = {                {1}, {2}, {3}, {4}        };        int[][] matrix4 = {                {1, 2},                {5, 6},                {3, 4},                {7, 8},        };        int[][] matrix5 = {                {1, 2, 3, 4}        };        printMatirxClockwisely(matrix5, 1, 4);    }    public void printMatirxClockwisely(int[][] matrix, int rows, int columns) {        r_upper_threshold = rows;        c_upper_threshold = columns;        r_lower_threshold = -1;        c_lower_threshold = -1;        int startRows = 0;        int startCols = 0;        while (startRows < r_upper_threshold && startCols < c_upper_threshold) {            printMatrixInCircle(matrix, startRows, startCols);            r_lower_threshold++;            c_lower_threshold++;            r_upper_threshold--;            c_upper_threshold--;            startRows++;            startCols++;        }    }    private void printMatrixInCircle(int[][] matrix ,int r, int c){        while (c < c_upper_threshold){            System.out.print(matrix[r][c] + " ");            c++;        }        c--;        r++;        while (r < r_upper_threshold) {            System.out.print(matrix[r][c] + " ");            r++;        }        r--;        c--;        while (c > c_lower_threshold && r != r_lower_threshold + 1) {            System.out.print(matrix[r][c] + " ");            c--;        }        c++;        r--;        while (r > r_lower_threshold + 1 && c != c_upper_threshold - 1) {            System.out.print(matrix[r][c] + " ");            r--;        }    }}

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