php實作排序演算法（一） 冒泡排序 快速排序

<code>冒泡排序是最简单基础的排序，但是由于好久没写代码了，一开始写下去还是不流畅。。。罪过罪过

冒泡排序原理，每次从待排序的序列里面选出一个最大或者最小的元素放到已经排好序的序列后面。知道最后待排序的序列为无；

以下是用php实现的冒泡排序，
注意以下几点：
1）当带排序的数组为无的时候直接退出，避免出错。
2) 尼玛数组都忘记怎么写了，我真是该死。
</code>

<code><span><?php</span><span><span>function</span><span>bubblesort</span><span>(<span>$array</span>)</span>{</span><span>$count</span> = count(<span>$array</span>);

        <span>if</span>(<span>$count</span> == <span>0</span>){
            <span>return</span><span>$array</span>;
        }
        <span>echo</span><span>$count</span>;
        <span>for</span>(<span>$i</span> = <span>0</span>; <span>$i</span> < <span>$count</span>; <span>$i</span>++){
            <span>for</span>(<span>$j</span> = <span>$count</span> - <span>1</span>; <span>$j</span> > <span>$i</span>; <span>$j</span>--){
                <span>if</span>(<span>$array</span>[<span>$j</span>] < <span>$array</span>[<span>$j</span> - <span>1</span>]){
                    <span>$temp</span> = <span>$array</span>[<span>$j</span>];
                    <span>$array</span>[<span>$j</span>] = <span>$array</span>[<span>$j</span>-<span>1</span>];
                    <span>$array</span>[<span>$j</span>-<span>1</span>] = <span>$temp</span>; 
                }
            }
        }
        <span>return</span><span>$array</span>;

    } 
    <span>$array</span> = <span>array</span>(<span>1</span>,<span>45</span>,<span>2</span>,<span>4</span>,<span>54</span>,<span>2</span>,<span>45</span>,<span>6</span>);
    print_r(bubblesort(<span>$array</span>));
    <span>?></span></code>

<code>    原理： 快速排序是对冒泡排序的一种改进，基本思想是通过一趟排序将要排序的数据分成两部分，其中的一部
</code>

<code><span><span><span><?php
    function quickSort<span>(<span>$arr</span>)</span>{
        <span>$count</span> = count<span>(<span>$arr</span>)</span>;
        if<span>(<span>$count</span> <= <span>1</span>)</span>{
            return <span>$arr</span>;
        }
        <span>$key</span> = <span>$arr</span>[<span>0</span>];
        <span>$left_arr</span> = array<span>()</span>;
        <span>$right_arr</span> = array<span>()</span>;
        for<span>(<span>$i</span> = <span>1</span>; <span>$i</span> < <span>$count</span>; <span>$i</span>++)</span>{
            if<span>(<span>$arr</span>[<span>$i</span>] <= <span>$key</span>)</span>{
                <span>$left_arr</span>[] = <span>$arr</span>[<span>$i</span>];
            }else{
                <span>$right_arr</span>[] = <span>$arr</span>[<span>$i</span>];
            }
        }

        <span>$left_arr</span> = quickSort<span>(<span>$left_arr</span>)</span>;
        <span>$right_arr</span> = quickSort<span>(<span>$right_arr</span>)</span>;
        return array_merge<span>(<span>$left_arr</span>,array<span>(<span>$key</span>)</span>,<span>$right_arr</span>)</span>;

    }

    <span>$arr</span> = array<span>(<span>23</span>,<span>4</span>,<span>6</span>,<span>46</span>,<span>34</span>,<span>23</span>,<span>6234</span>,<span>34</span>,<span>12</span>,<span>34</span>)</span>;
    print_r<span>(quickSort<span>(<span>$arr</span>)</span>)</span>;</span></span></span></code>