php纯原生实现数组二分法

代码如下

$arr = [1,3,5,7,9];//$arr = range(1,10000);var_dump(find($arr, 2));

function find(array $arr, $seach)
	{
		$left  = 0;
		$right = count($arr) - 1;
		if($seach > $arr[$right]) {
			return $arr[0];
		}
		while($left < $right) {
			$mod = (($left + $right +1) >> 1);
			echo $mod,‘<br >‘;
			if($mod == $right) {
				return $arr[$mod];
			}
			if($arr[$mod] < $seach) {
				$left = $mod;
			} else if ($arr[$mod] > $seach) {
				$right = $mod;
			} else {
				return $arr[$mod];
			}
		}
		return false;
	}