PHP面试常见算法

//字符串的反转

$str = 'abcdefght';
function str_rev($str)
{
	for($i=0;true;$i++)
	{
		if(!isset($str[$i])){ break;}
	}
	$newstr = '';
	for($j=$i-1;$j>=0;$j--)
	{
		$newstr .= $str[$j];
	}
	echo $newstr;
}
str_rev($str);
echo "<hr />";

//数组的合并

function array_mer()
{
	$newarr = [];
	$arr = func_get_args();
	foreach ($arr as $value) {
		if(is_array($value)){
			foreach ($value as $v) {
				$newarr[] = $v; 
			}
		}
	}
	return $newarr;
}

print_r(array_mer([2],[22,33],[44,455,666]));
echo "<hr />";

//猴子选大王

function king($n,$m){
	$monkeys = range(1,$n);
	$i = 0;
	while (count($monkeys)>1) {
		if(($i+1)%$m==0){
			unset($monkeys[$i]);
		}else{
			array_push($monkeys,$monkeys[$i]);
			unset($monkeys[$i]);
		}
		$i++;
	}
	return current($monkeys);
}
echo king(10,3);
echo "<hr />";

//冒泡算法

function maopao($arr){
	$len = count($arr);
	for($k=0;$k<=$len;$k++){
		for($j=$len-1;$j>$k;$j--){
			if($arr[$j]<$arr[$j-1]){
				$temp = $arr[$j];
				$arr[$j] = $arr[$j-1];
				$arr[$j-1] = $temp;
			}

		}
	}
	return $arr;
}
$arr = [33,1,6,5,99,75,22,24,31];
var_dump(maopao($arr));
echo "<hr />";

//递归算法

function call($len){
	static $i = 0;
	echo $i.PHP_EOL;
	$i++;
	if($i < $len){
		return call($len);
	}
}
call(10);