冒泡排序与选择排序

示例数组：

$array = [62, 88, 58, 47, 62, 35, 73, 51, 99, 37, 93];

一、冒泡排序

将数组分为有序和无序两部分，无序序列中的相邻元素进行比较，如果前面的元素值大于后边的元素值，两者交换，第一轮排序后，最大值（99）会放入有序序列的最前边（10的位置），即有序序列中的元素为[99]，如下所示：

Array ( [0] => 62 [1] => 58 [2] => 47 [3] => 62 [4] => 35 [5] => 73 [6] => 51 [7] => 88 [8] => 37 [9] => 93 [10] => 99 ) 

第二轮排序，同理，无序序列中从第一个元素开始，相邻元素相比较，如果前者大于后者，交换数据，在9的位置结束（10为有序序列的位置），第二轮排序结束后，第二轮的最大元素插入有序序列的最前边（93在9的位置），即有序序列的元素为[93,99]，结果如下所示：

Array ( [0] => 58 [1] => 47 [2] => 62 [3] => 35 [4] => 62 [5] => 51 [6] => 73 [7] => 37 [8] => 88 [9] => 93 [10] => 99 )

以此类推，经过10轮完成排序，如下：

第1次排序结束
Array ( [0] => 62 [1] => 58 [2] => 47 [3] => 62 [4] => 35 [5] => 73 [6] => 51 [7] => 88 [8] => 37 [9] => 93 [10] => 99 ) 

第2次排序结束
Array ( [0] => 58 [1] => 47 [2] => 62 [3] => 35 [4] => 62 [5] => 51 [6] => 73 [7] => 37 [8] => 88 [9] => 93 [10] => 99 ) 

第3次排序结束
Array ( [0] => 47 [1] => 58 [2] => 35 [3] => 62 [4] => 51 [5] => 62 [6] => 37 [7] => 73 [8] => 88 [9] => 93 [10] => 99 ) 

第4次排序结束
Array ( [0] => 47 [1] => 35 [2] => 58 [3] => 51 [4] => 62 [5] => 37 [6] => 62 [7] => 73 [8] => 88 [9] => 93 [10] => 99 ) 

第5次排序结束
Array ( [0] => 35 [1] => 47 [2] => 51 [3] => 58 [4] => 37 [5] => 62 [6] => 62 [7] => 73 [8] => 88 [9] => 93 [10] => 99 ) 

第6次排序结束
Array ( [0] => 35 [1] => 47 [2] => 51 [3] => 37 [4] => 58 [5] => 62 [6] => 62 [7] => 73 [8] => 88 [9] => 93 [10] => 99 ) 

第7次排序结束
Array ( [0] => 35 [1] => 47 [2] => 37 [3] => 51 [4] => 58 [5] => 62 [6] => 62 [7] => 73 [8] => 88 [9] => 93 [10] => 99 ) 

第8次排序结束
Array ( [0] => 35 [1] => 37 [2] => 47 [3] => 51 [4] => 58 [5] => 62 [6] => 62 [7] => 73 [8] => 88 [9] => 93 [10] => 99 ) 

第9次排序结束
Array ( [0] => 35 [1] => 37 [2] => 47 [3] => 51 [4] => 58 [5] => 62 [6] => 62 [7] => 73 [8] => 88 [9] => 93 [10] => 99 ) 

第10次排序结束
Array ( [0] => 35 [1] => 37 [2] => 47 [3] => 51 [4] => 58 [5] => 62 [6] => 62 [7] => 73 [8] => 88 [9] => 93 [10] => 99 ) 

二、选择排序

将数组分为有序与无序两部分，有序序列在前边，无序序列在后边，每一轮排序将无序序列中的第一个元素与剩余元素进行比较，找到最小元素后放到有序序列的最后。

第一轮排序，有序序列默认为空，找出数组中的最小元素（35），放入有序序列中（有序序列元素只有35一个元素），结果如下：

Array ( [0] => 35 [1] => 88 [2] => 62 [3] => 58 [4] => 62 [5] => 47 [6] => 73 [7] => 51 [8] => 99 [9] => 37 [10] => 93 ) 

以此类推，10轮排序后结束，如下：

第1次排序结束
Array ( [0] => 35 [1] => 88 [2] => 62 [3] => 58 [4] => 62 [5] => 47 [6] => 73 [7] => 51 [8] => 99 [9] => 37 [10] => 93 ) 

第2次排序结束
Array ( [0] => 35 [1] => 37 [2] => 88 [3] => 62 [4] => 62 [5] => 58 [6] => 73 [7] => 51 [8] => 99 [9] => 47 [10] => 93 ) 

第3次排序结束
Array ( [0] => 35 [1] => 37 [2] => 47 [3] => 88 [4] => 62 [5] => 62 [6] => 73 [7] => 58 [8] => 99 [9] => 51 [10] => 93 ) 

第4次排序结束
Array ( [0] => 35 [1] => 37 [2] => 47 [3] => 51 [4] => 88 [5] => 62 [6] => 73 [7] => 62 [8] => 99 [9] => 58 [10] => 93 ) 

第5次排序结束
Array ( [0] => 35 [1] => 37 [2] => 47 [3] => 51 [4] => 58 [5] => 88 [6] => 73 [7] => 62 [8] => 99 [9] => 62 [10] => 93 ) 

第6次排序结束
Array ( [0] => 35 [1] => 37 [2] => 47 [3] => 51 [4] => 58 [5] => 62 [6] => 88 [7] => 73 [8] => 99 [9] => 62 [10] => 93 ) 

第7次排序结束
Array ( [0] => 35 [1] => 37 [2] => 47 [3] => 51 [4] => 58 [5] => 62 [6] => 62 [7] => 88 [8] => 99 [9] => 73 [10] => 93 ) 

第8次排序结束
Array ( [0] => 35 [1] => 37 [2] => 47 [3] => 51 [4] => 58 [5] => 62 [6] => 62 [7] => 73 [8] => 99 [9] => 88 [10] => 93 ) 

第9次排序结束
Array ( [0] => 35 [1] => 37 [2] => 47 [3] => 51 [4] => 58 [5] => 62 [6] => 62 [7] => 73 [8] => 88 [9] => 99 [10] => 93 ) 

第10次排序结束
Array ( [0] => 35 [1] => 37 [2] => 47 [3] => 51 [4] => 58 [5] => 62 [6] => 62 [7] => 73 [8] => 88 [9] => 93 [10] => 99 ) 

两者共同点：

将数组分为有序序列与无序序列，将每轮筛选出来的元素插入有序序列，黄的部分为有序序列

不同点：

冒泡排序——相邻元素比较，找出最大值，放入有序序列的最前边；

选择排序——用无序序列中的第一个元素与剩余无序序列元素进行比较，找出最小元素，插入有序序列的最后边