Insertion Sort Implementation in PHP

Insertion sort works by assuming the sub‑array before the current element is already sorted, then inserting the current element into its proper place by shifting larger elements one position to the right; this process repeats until the entire array is sorted, and the algorithm is stable.

The following PHP function implements insertion sort on an array of numbers, iterating from the second element, comparing it with previous elements, shifting larger values, and inserting the element at the correct position before returning the sorted array.

function insertArrMethod($arr) {
    $count = count($arr);
    for ($i = 1; $i < $count; $i++) {
        //以数组第一个数字为基准
        $temp = $arr[$i];
        //控制循环并进行交换
        for ($j = $i - 1; $j >= 0; $j--) {
            if ($temp < $arr[$j]) {
                $arr[$j + 1] = $arr[$j];
                $arr[$j] = $temp;
            } else {
                break;
            }
        }
    }
    return $arr;
}

$array = insertArrMethod([12,56,32,58,1,25,4,63,21,105,99]);
print_r($array);

The function call sorts the sample array and prints the resulting ordered list, demonstrating the correct operation of the insertion sort algorithm.