How to implement matrix in php code

The method of implementing the matrix in php code: first take out the number of rows and columns; then control the number of turns in the outer loop; then pass "j=i;j

The operating environment of this article: windows7 system, PHP7.1 version, DELL G3 computer

[PHP] Algorithm - Print clockwise PHP implementation of matrix

1. Take out the number of rows and columns, row, col, and the number of circles are (smaller value -1)/2 1

2. Outer loop Control the number of circles, the inner four for loops, i

3. The first for loop, from left to right, j=i;j

4. The second for loop, from top to bottom, k=i 1;k

5. The third loop, from right to left, m=col-2-i;m>=i&&row-1-i!=i;m-- arr[row-1-i][m]// When row-1-i!=i is a single row, it is only printed once

6. The fourth loop, from bottom to top, n=row-2-i;n>=i&&col-1-i!= i;n-- arr[n][i]

<?php
$arr=array();
$flag=0;
for($i=0;$i<2;$i++){
        $flag=$i*2;
        for($j=0;$j<2;$j++){
                $flag++;
                $arr[$i][]=$flag;
        }   
}
var_dump($arr);
//顺时针打印矩阵
function printMatrix($arr){
        $res=array();
        $row=count($arr);
        $col=count($arr[0]);
        $circle=intval((($row>$col ? $col : $row)-1)/2+1);
        for($i=0;$i<$circle;$i++){
                //转圈开始
                //从左到右
                for($j=$i;$j<=$col-1;$j++){
                        $t=$arr[$i][$j];
                        if(in_array($t,$res)) continue;
                        $res[]=$t;
                }   
                //从上到下
                for($k=$i+1;$k<$row-$i;$k++){
                        $t=$arr[$k][$col-$i-1];
    
                        if(in_array($t,$res)) continue;
                        $res[]=$t;
                }   
                //从右到左
                for($m=$col-$i-2;$m>=$i;$m--){
                        $t=$arr[$row-$i-1][$m];
                        if(in_array($t,$res)) continue;
                        $res[]=$t;
                }   
                //从下到上
                for($n=$row-$i-2;$n>$i;$n--){
                        $t=$arr[$n][$i];
                        if(in_array($t,$res)) continue;
                        $res[]=$t;
                }   
        }   
        return $res;
}
$res=printMatrix($arr);

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