PHP Bubble Sort Binary Search Sequential Search Detailed Explanation of Two-Dimensional Array Sorting Algorithm Function_PHP Tutorial

Data structure is very important, algorithm + data structure + document = program
Use PHP to describe the bubble sort algorithm, the object can be an array

Copy code The code is as follows:

//Bubble sort (array sort)
function bubble_sort($array) {
$count = count( $array);
if ($count <= 0)
return false;
for($i=0; $i<$count; $i++){
for($j= $count-1; $j>$i; $j–){
if ($array[$j] < $array[$j-1]){
$tmp = $array[$j ];
$array[$j] = $array[$j-1];
$array[$j-1] = $tmp;
}
}
}
return $array; }

Use PHP to describe sequential search and binary search (also called half search) algorithms. Sequential search must consider efficiency, and the object can be an ordered array

Copy code The code is as follows:

//Binary search (search for an element in an array)
function bin_sch( $array, $low, $high, $k){
if ($low <= $high){
$mid = intval(($low+$high)/2);
if ( $array[$mid] == $k){
return $mid;
}elseif ($k < $array[$mid]){
return bin_sch($array, $low, $ mid-1, $k);
}else{
return bin_sch($array, $mid+1, $high, $k);
}
}
return -1;
}
//Sequential search (search for an element in the array)
function seq_sch($array, $n, $k){
$array[$n] = $k;
for($i=0; $i<$n; $i++){
if($array[$i]==$k){
break;
}
}
if ($i<$n){
return $i;
}else{
return -1;
}
}

Write a two-dimensional array sorting algorithm function, which can be universal. You can call PHP built-in function

Copy the code The code is as follows:

//Two-dimensional array sorting, $arr is the data, $keys is the key value of sorting, $order is the sorting rule, 1 is ascending order, 0 is descending order
function array_sort($ arr, $keys, $order=0) {
if (!is_array($arr)) {
return false;
}
$keysvalue = array();
foreach($ arr as $key => $val) {
$keysvalue[$key] = $val[$keys];
}
if($order == 0){
asort($ keysvalue);
}else {
arsort($keysvalue);
}
reset($keysvalue);
foreach($keysvalue as $key => $vals) {
$keysort[$key] = $key;
}
$new_array = array();
foreach($keysort as $key => $val) {
$new_array[$key ] = $arr[$val];
}
return $new_array;
}

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