面试题 20: 顺时针打印矩阵

package week_4;
/**难度系数:***
* 剑指offer: 顺时针打印矩阵
* 方法: 找规律
* 测试用例:数组只有一行,一列,一行一列,二行二列,多行多列,为空
* @author dingding
* Date:2017-7-8 14:10
* Declaration: All Rights Reserved!
*/
public class No20 {

public static void main(String[] args) {
test1();
test2();
test3();
test4();
test5();
}

//solution
private static void printMatrixClockwisely(int[][] numbers,int columns,int rows){
if (numbers == null || columns<=0 || rows <=0) {
return;
}
int start = 0;
while (columns >start*2 && rows >start*2){
printMatrixInCircle(numbers,columns,rows,start);
++start;
}
}

//顺时针打印
private static void printMatrixInCircle(int[][] numbers, int columns, int rows, int start) {
int endX = columns - 1 -start;  //列
int endY = rows - 1 -start;     //行

//从左到右打印一行
for(int i=start;i<=endX;++i){
int number = numbers[start][i];
System.out.print(" "+number);
}

//从上到下打印一列
if (start<endY) {
for (int i = start+1;i<=endY;++i){
int number = numbers[i][endX];
System.out.print(" "+number);
}
}

//从右到左打印一行
if (start<endX && start<endY) {
for (int i=endX-1;i>=start;--i){
int number = numbers[endY][i];
System.out.print(" "+number);
}
}

//从下到上打印一列
if (start < endX && start < endY-1) {
for (int i=endY-1;i>=start+1;--i){
int number = numbers[i][start];
System.out.print(" "+number);
}
}
}

private static void test1() {
int numbers[][]= {{1,2,3}};
printMatrixClockwisely(numbers, numbers[0].length, numbers.length);
System.out.println();
System.out.println("================test1===================");
}

private static void test2() {
int numbers[][]= {{1},{2}};
printMatrixClockwisely(numbers, numbers[0].length, numbers.length);
System.out.println();
System.out.println("================test2===================");
}

private static void test3() {
int numbers[][]= {{1,2,3,4},{1,2,3,4},{1,2,3,4},{1,2,3,4}};
printMatrixClockwisely(numbers, numbers[0].length, numbers.length);
System.out.println();
System.out.println("================test3===================");
}

private static void test4() {
int numbers[][]= {{1}};
printMatrixClockwisely(numbers, numbers[0].length, numbers.length);
System.out.println();
System.out.println("================test4===================");
}

private static void test5() {
int numbers[][]= {{1,2,3,4,5},{6,7,8,9,10},{11,12,13,14,15}};
printMatrixClockwisely(numbers, numbers[0].length, numbers.length);
}

}