Several commonly used sorting methods (PHP implementation)

1. Normal bubble sort

<?php    function Buddle_sort ($a) {        $i =0;        $j =0;        $n = sizeof ($a);        if ($n ==0)        {return false;                    } else{for                                      ($i =0; $i < $n; $i + +)        {for            ($j = $n-1; $j > $i; $j-)           {                    if ($a [$j]> $a [$i]) {                    $m = $a [$i];                    $a [$i]= $a [$j];                    $a [$j]= $m;                    }    }} return $a;    } $l = Array (20,10,15,4,2,45,11), $R =buddle_sort ($l), foreach ($R as $value) echo $value, "_";? >

2. Improved bubble sorting

<?php    function Buddle_sort ($a) {        $i =0;        $j =0;        $n = sizeof ($a);        if ($n ==0)        {return false;                    } else{                     $flag = true;                 for ($i = $n-1; $i >0 && $flag; $i-)        {$flag = false;           for ($j =0; $j < $i; $j + +)           {                    if ($a [$j]> $a [$j +1]) {                    $m = $a [$j +1];                    $a [$j +1]= $a [$j];                    $a [$j]= $m;                    $flag = true;    }}} return $a;    } $l = Array (10,15,20,25,30,31,5), $R =buddle_sort ($l), foreach ($R as $value) echo $value, "_";? >

3. Select sort

<?php    function Buddle_sort ($a) {        $i =0;        $j =0;        $n = sizeof ($a);        if ($n ==0)        {return false;                    } else{for                                      ($i = $n-1; $i >0; $i-)        {   $max = $i;           for ($j =0; $j < $i; $j + +)           {                    if ($a [$j]> $a [$max]) {                    $max = $j;                    }                             }           if ($a [$max] > $a [$i])           {               $m = $a [$i];               $a [$i]= $a [$max];               $a [$max] = $m;           }        }             }    return $a;    } $l = Array (10,1,2,5,30,31,6), $R =buddle_sort ($l), foreach ($R as $value) echo $value, "_";? >

4. Insert Sort

<?phpfunction Simple_sort ($a) {    $l = sizeof ($a);    if (! $l) {        return false;    }    for ($i =1; $i < $l; $i + +) {       if ($a [$i]< $a [$i-1]) {for                      ($j = $i; $j >0; $j-) {                             if ($a [$j]< $a [$i])               {break                  ;                }            }             $v = $a [$i];            for ($m = $i; $m > $j +1; $m-)            {            $a [$m]= $a [$m-1];            }            $a [$j +1] = $v;                         }}        return $a;} $s =array (2,13,5,12,6,67,54,12), $R =simple_sort ($s); foreach ($R as $value) {echo $value, "_";}

5.1, Waste space

<?phpfunction QuickSort ($arr) {    if (count ($arr) >1) {        $k = $arr [0];        $x =array ();        $y =array ();        $_size=count ($arr);        for ($i =1; $i <$_size; $i + +) {            if ($arr [$i]<= $k) {                $x []= $arr [$i];            } ElseIf ($arr [$i]> $k) {                $y []= $arr [$i];            }        }        $x =quicksort ($x);        $y =quicksort ($y);        Return Array_merge ($x, Array ($k), $y);    } else{        return $arr;    }} $a =array (2,1,2,4,12,5,6,8); $r = QuickSort ($a); Var_dump ($R); >

6. Fast row 2, recommended, in an array to implement.

<?php$a = Array (2, 1, 5, 3, 6, 4, 8, 9, 1), function partition (& $a, $low, $high) {    $pivot = $a [$low];    while ($low < $high) {        while ($low < $high && $a [$high] >= $pivot) {            $high--;        }        $a [$low] = $a [$high];        while ($low < $high && $a [$low] <= $pivot) {            $low + +;        }        $a [$high] = $a [$low];    }    $a [$low] = $pivot;    return $low;} Function qs (& $a, $low, $high) {    if ($low < $high) {        $p = partition ($a, $low, $high);        QS ($a, $low, $p-1);        QS ($a, $p +1, $high);    }} QS ($a, 0, 8); Var_dump ($a);

　　

Several commonly used sorting methods (PHP implementation)