[php算法]查找和排序

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'; } //交换数据 function swap(&$a, &$b) { $tmp = $a; $a = $b; $b = $tmp; } //快速排序 function quick_sort($a) { if (count($a) <= 1) { return $a; } $l = array(); $r = array(); $x = $a[0]; $c = count($a); for ($i = 1; $i < $c; $i++) { if ($a[$i] <= $x) { $l[] = $a[$i]; } else { $r[] = $a[$i]; } } $l = quick_sort($l); $r = quick_sort($r); return array_merge($l, array($x), $r); } //选择排序 function select_sort($a) { $n = count($a); for ($i = 0; $i < $n; $i++) { $min = $i; for ($j = $i + 1; $j < $n; $j++) { if ($a[$j] < $a[$min]) { $min = $j; } } swap($a[$i], $a[$min]); } return $a; } //插入排序 function insert_sort($a) { $n = count($a); for ($i = 1; $i < $n; $i++) { if ($a[$i] < $a[$i - 1]) { $temp = $a[$i]; for ($j = $i - 1; (($j >= 0) && $a[$j] > $temp); $j--) { $a[$j + 1] = $a[$j]; } $a[$j + 1] = $temp; } } return $a; } //冒泡排序 function bubble_sort($a) { $n = count($a); for ($i = 0; $i < $n; $i++) { for ($j = $i; $j < $n; $j++) { if ($a[$i] > $a[$j]) { swap($a[$i], $a[$j]); } } } return $a; } //希尔排序 function shell_sort($a) { $n = count($a); for ($gap = $n / 2; $gap > 0; $gap = intval($gap / 2)) { for ($i = $gap; $i < $n; $i++) { //从gap开始, if ($a[$i] < $a[$i - $gap]) { //从$gap开始，每个元素与自己组内的数据进行直接插入排序 $temp = $a[$i]; for ($k = $i - $gap; ($k >= 0 && $a[$k] > $temp); $k-=$gap) { $a[$k + $gap] = $a[$k]; } $a[$k + $gap] = $temp; } } } return $a; } //顺序查找 function sequential_search($a, $finded) { $length = count($a); for ($i = 0; $i < $length; $i++) { if ($a[$i] == $finded) { return $i; } } return -1; } //折半查找 || 二分查找 function half_search($a, $low, $hight, $finded) { while ($low <= $hight) { $middle = intval(($low + $hight) / 2); if ($a[$middle] == $finded) { return $middle; } else if ($a[$middle] < $finded) { $low = $middle + 1; } else if ($a[$middle] > $finded) { $hight = $middle - 1; } } return -1; } //排列组合 class Permutation { var $srcList; //存放原始数列数组 var $rstList; //存放最终数列数组 var $srcLen; //原始数列的长度 var $rstLen; //结果数列的长度 var $rstOrder; //求排列或组合标志 function Permutation($m) { if (!is_array($m)) { echo "参数类型错误：Permutation(array $m) $m为数组类型"; return false; } $this->srcLen = count($m); $this->srcList = $m; } //取得排列组合结果, $order=1为取排列,$order=2为取组合 function getList($n, $order = 1) { if (!is_int($n)) { echo "参数类型错误：getList(int $n) $n为整数类型"; return false; } if ($n > $this->srcLen) { echo "要求的排列组合的长度不能大于原始数列的长度"; return false; } $this->rstLen = $n; $this->rstOrder = $order; $this->rstList = array(); $this->doPermutation($this->srcList, $this->rstLen); return $this->rstList; } //递归计算从m中取n的排列, $rst存取出的排列 function doPermutation($m, $n, &$rst = array()) { //如果已经取完 if ($n == 0) { $this->rstList[] = $rst; $rst = array(); return true; } //从当前数列m中选取一个值，并更新数列m foreach ($m as $key => $value) { $nextM = $m; //判断是取排列还是组合 switch ($this->rstOrder) { //取排列, 清空当前取出的值 case 1: unset($nextM[$key]); break; //取组合, 清空当前及前面所取的值 case 2: array_splice($nextM, 0, $key + 1); break; default:unset($nextM[$key]); break; } $nextRst = $rst; //将取的值放到结果数列中 $nextRst[] = $value; $this->doPermutation($nextM, $n - 1, $nextRst); } } } $m = array(0, 1, 2, 3, 4, 5); $p = new Permutation($m); $arr = $p->getList(3, 1); foreach ($arr as $value) { echo implode(",", $value) . "
"; }