# 7. Reverse Integer

Given a 32-bit signed integer, reverse digits of an integer.

**Example 1:**

**Input:**

123

**Output:**

321

**Example 2:**

**Input:**

-123

**Output:**

-321

**Example 3:**

**Input:**

120

**Output:**

21

**Note:**

Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−2^{31}, 2^{31 }− 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

class Solution { /** * @param Integer $x * @return Integer */ function reverse($x) { $r = (int) (strrev(trim($x,"+-")) * ($x>0?1:-1)); if($r > pow(2,31)-1 || $r < -pow(2,31)){ return 0; } return $r; } }

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