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java-51-输入一个矩阵,按照从外向里以顺时针的顺序依次打印出每一个数字。...

程序员文章站 2022-07-12 09:13:48
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public class PrintMatrixClockwisely {

/**
* Q51.输入一个矩阵,按照从外向里以顺时针的顺序依次打印出每一个数字。
例如:如果输入如下矩阵:

1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16

则依次打印出数字1, 2, 3, 4, 8, 12, 16, 15, 14, 13, 9, 5, 6, 7, 11, 10。
*/
public enum Direction{
left,right,up,down,
}
public static void main(String[] args) {
int[][] matrix= {
{ 1, 2, 3, 4, 5},
{ 6, 7, 8, 9,10},
{11,12,13,14,15},
{16,17,18,19,20},
{21,22,23,24,25},
};
printMatrixClockwisely(matrix);
}

/*
* 思路比较直观,
* 从左往右打印,到了右边界则向下,到了下边界就往左,到了左边界就往上。
* 注意结束条件以及打印的时机
*/
public static void printMatrixClockwisely(int[][] matrix){

int rowLen=matrix.length;
int columnLen=matrix[0].length;
Direction direction=Direction.right;
int upBound=0;
int downBound=rowLen-1;
int leftBound=0;
int rightBound=columnLen-1;
int row=0;
int column=0;
while(true){
System.out.print(matrix[row][column]+" ");
//2 3 4 5 10 15 20 25 24 23 22 21 16 11 6 7 8 9 14 19 18 17 12 13
if(upBound==downBound&&leftBound==rightBound){
break;
}
switch (direction){
case right:
if(column<rightBound){
++column;
}else{
++row;
direction=Direction.down;
++upBound;
}
break;
case down:
if(row<downBound){
++row;
}else{
--column;
direction=Direction.left;
--rightBound;
}
break;
case up:
if(row>upBound){
--row;
}else{
++column;
direction=Direction.right;
++leftBound;
}
break;
case left:
if(column>leftBound){
--column;
}else{
--row;
direction=Direction.up;
--downBound;
}
break;
default:break;
}
}

}
}