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PHP implements bubble sort, selection sort, insertion sort and quick sort quick sort method quick sort c language quick sort algorithm c language
PHP implements bubble sort, selection sort, insertion sort and quick sort quick sort method quick sort c language quick sort algorithm c language
I have read the four basic sorting methods in C language before when I was studying data structure by myself. I have almost forgotten the C language. Recently, when I had time, I re-wrote the four sorting methods in PHP to review the increasingly unfamiliar algorithms. . Paste the code directly.
<?php
/**
* 打印数据，用于调试
* @param var 打印对象
*/
function p($var){
echo "<pre class="brush:php;toolbar:false">";
print_r($var);
echo "";
}
$arr=array(33,11,22,66,55,44,88,99,77);
printf("**原数组**");
p($arr);
/**
*冒泡排序法
* @param $arr 排序数组
*思路：和相邻的数字对比，每次对比如果左边比右边大则交换位置。
*两个节点，一个方向：两次循环次数，冒泡方向（即$j的初值和终止条件）
*num的作用是做了优化，一旦循环没有交换则冒泡已完成
**/
function bubbleSort($arr){
print("**冒泡排序法**");
$len=count($arr);
$temp=0;
$num=1;
for ($i=0; ($i < $len-1)&&($num>0); $i++) {
$num=0;
for ($j=$len-1; $j>$i; $j--) {
if($arr[$j]>$arr[$j-1]){
continue;
}else{
//冒泡交换
$temp=$arr[$j-1];
$arr[$j-1]=$arr[$j];;
$arr[$j]=$temp;
$num++;
}
}
}
return $arr;
}
p(bubbleSort($arr));
/**
*选择排序法
* @param $arr 排序数组
*思路：每一轮循环，找出最小的数字，把其下标保存到最左方数字
*而找出最小数字的方法是：和右方数字比较，若右方比较小，则保存其下标，再将此下标对应的值和
*下一个右方数字比较直到所有右方数字比较一遍，再将此最小值存放在最左方数字
**/
function selectSort($arr){
print("**选择排序法**");
$len=count($arr);
$buff=0;
for ($i=0; $i < $len-1; $i++) {
$temp=$i;
for ($j=$i; $j < $len-1; $j++) {
if($arr[$temp]>$arr[$j+1]){
$temp=$j+1;//若右方数字更小，则保存其下标，用来跟后面的数据比较
}
}
//得到最小的数字下标
if($temp!=$i){
//如果下标不是$i则交换，不然就没必要
$buff=$arr[$temp];
$arr[$temp]=$arr[$i];
$arr[$i]=$buff;
}
}
return $arr;
}
p(selectSort($arr));
/**
*插入排序法
* @param $arr 排序数组
*思路：假设前面的数已经是排好顺序的，现在要把第n个数插到前面的有序数中。即把第二个数据插入到
*第一个数据之中，使其形成一个有序数组，然后再讲第三个数插入到前面两个数组成的有序数组中，形成
*有序数组，如此反复最后完成排序
**/
function insertSort($arr){
print("**插入排序法**");
$len=count($arr);
for ($i=1; $i < $len; $i++) {
$temp=$arr[$i];//将要插入的数据缓存
for ($j=$i-1; $j >=0; $j--) {
if($temp<$arr[$j]){
$arr[$j+1]=$arr[$j];//如果要插入的数据比原数组的最后一个小，则与之交换
$arr[$j]=$temp;
}else break;
}
}
return $arr;
}
p(insertSort($arr));
/**
*快速排序法
* @param $arr 排序数组
*思路：选择一个基准元素，通过一趟扫描，将待排序列分成两部分，再对每一部分递归调用自己方法
*最后返回左边排序好的数组和右边排序好的数组和基准元素合并，就是有序数组了。
**/
function quickSort($arr){
$len=count($arr);
if($len<=1) return $arr;
$baseNum=$arr[0];
$leftArr=$rightArr=array();
//根据基准元素分成两部分
for ($i=1; $i < $len; $i++) {
if ($arr[$i]<=$arr[0]) {
$leftArr[]=$arr[$i];
}else{
$rightArr[]=$arr[$i];
}
}
$leftArr=quickSort($leftArr);//递归调用
$rightArr=quickSort($rightArr);
return array_merge($leftArr,array($baseNum),$rightArr);
}
print("**快速排序法**");
p(quickSort($arr));
?>
Running result:
The above introduces the implementation of bubble sort, selection sort, insertion sort and quick sort in PHP, including quick sort and insertion sort. I hope it will be helpful to friends who are interested in PHP tutorials.
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