php 笛卡尔积的算法实现
php 笛卡尔积的算法实现
<?php
$arr = array(array(1,3,4,5),array(3,5,7,9),array(76,6,1,0));
/**
** 实现二维数组的笛卡尔积组合
** $arr 要进行笛卡尔积的二维数组
** $str 最终实现的笛卡尔积组合,可不写
** @return array
**/
function cartesian($arr,$str = array()){
//去除第一个元素
$first = array_shift($arr);
//判断是否是第一次进行拼接
if(count($str) > 1) {
foreach ($str as $k => $val) {
foreach ($first as $key => $value) {
//最终实现的格式 1,3,76
//可根据具体需求进行变更
$str2[] = $val.','.$value;
}
}
}else{
foreach ($first as $key => $value) {
//最终实现的格式 1,3,76
//可根据具体需求进行变更
$str2[] = $value;
}
}
//递归进行拼接
if(count($arr) > 0){
$str2 = cartesian($arr,$str2);
}
//返回最终笛卡尔积
return $str2;
}
$cartesian_product = cartesian($arr);
print_r($cartesian_product);
?>最终输出格式
Array ( [0] => 1,3,76 [1] => 1,3,6 [2] => 1,3,1 [3] => 1,3,0 [4] => 1,5,76 [5] => 1,5,6 [6] => 1,5,1 [7] => 1,5,0 [8] => 1,7,76 [9] => 1,7,6 [10] => 1,7,1 [11] => 1,7,0 [12] => 1,9,76 [13] => 1,9,6 [14] => 1,9,1 [15] => 1,9,0 [16] => 3,3,76 [17] => 3,3,6 [18] => 3,3,1 [19] => 3,3,0 [20] => 3,5,76 [21] => 3,5,6 [22] => 3,5,1 [23] => 3,5,0 [24] => 3,7,76 [25] => 3,7,6 [26] => 3,7,1 [27] => 3,7,0 [28] => 3,9,76 [29] => 3,9,6 [30] => 3,9,1 [31] => 3,9,0 [32] => 4,3,76 [33] => 4,3,6 [34] => 4,3,1 [35] => 4,3,0 [36] => 4,5,76 [37] => 4,5,6 [38] => 4,5,1 [39] => 4,5,0 [40] => 4,7,76 [41] => 4,7,6 [42] => 4,7,1 [43] => 4,7,0 [44] => 4,9,76 [45] => 4,9,6 [46] => 4,9,1 [47] => 4,9,0 [48] => 5,3,76 [49] => 5,3,6 [50] => 5,3,1 [51] => 5,3,0 [52] => 5,5,76 [53] => 5,5,6 [54] => 5,5,1 [55] => 5,5,0 [56] => 5,7,76 [57] => 5,7,6 [58] => 5,7,1 [59] => 5,7,0 [60] => 5,9,76 [61] => 5,9,6 [62] => 5,9,1 [63] => 5,9,0 )
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