不用递归实现无限级分类，简单测试了下性能比递归稍好一点点点，但写得太复杂了，还是递归简单方便点

代码：

<?php

$list = array(

    array('id'=>1, 'pid'=>0, 'deep'=>0, 'name'=>'test1'),

    array('id'=>2, 'pid'=>1, 'deep'=>1, 'name'=>'test2'),

    array('id'=>3, 'pid'=>0, 'deep'=>0, 'name'=>'test3'),

    array('id'=>4, 'pid'=>2, 'deep'=>2, 'name'=>'test4'),

    array('id'=>5, 'pid'=>2, 'deep'=>2, 'name'=>'test5'),

    array('id'=>6, 'pid'=>0, 'deep'=>0, 'name'=>'test6'),

    array('id'=>7, 'pid'=>2, 'deep'=>2, 'name'=>'test7'),

    array('id'=>8, 'pid'=>5, 'deep'=>3, 'name'=>'test8'),

    array('id'=>9, 'pid'=>3, 'deep'=>2, 'name'=>'test9'),

);

function resolve($list) {

    $newList = $manages = $deeps = $inDeeps = array();

    foreach ($list as $row) {

        $newList[$row['id']] = $row;

    }

    $list = null;

    foreach ($newList as $row) {

        if (! isset($manages[$row['pid']]) || ! isset($manages[$row['pid']]['children'][$row['id']])) {

            if ($row['pid'] > 0 && ! isset($manages[$row['pid']]['children'])) $manages[$row['pid']] = $newList[$row['pid']];

            $manages[$row['pid']]['children'][$row['id']] = $row;

        }

        if (! isset($inDeeps[$row['deep']]) || ! in_array($row['id'], $inDeeps[$row['deep']])) {

            $inDeeps[$row['deep']][] = array($row['pid'], $row['id']);

        }

    }

    krsort($inDeeps);

    array_shift($inDeeps);

    foreach ($inDeeps as $deep => $ids) {

        foreach ($ids as $m) {

            // 存在子栏目的进行转移

            if (isset($manages[$m[1]])) {

                $manages[$m[0]]['children'][$m[1]] = $manages[$m[1]];

                $manages[$m[1]] = null;

                unset($manages[$m[1]]);

            }

        }

    }

    return $manages[0]['children'];

}

递归实现

function resolve2(& $list, $pid = 0) {

    $manages = array();

    foreach ($list as $row) {

        if ($row['pid'] == $pid) {

            $manages[$row['id']] = $row;

            $children = resolve2($list, $row['id']);

            $children && $manages[$row['id']]['children'] = $children;

        }

    }

    return $manages;

}