How to reverse integer in php

php method to implement integer reversal: 1. Create a PHP sample file; 2. Use the "function reverse($x) {...}" method to achieve integer reversal.

#The operating environment of this article: Windows7 system, PHP7.1, Dell G3.

How to achieve integer reversal in php?

PHP algorithm integer reversal

Given a 32-bit signed integer, you need to reverse the digits on each bit of this integer. change.

Example 1:

Input: 123

Output: 321

Example 2:

Input: -123

Output: -321

Example 3:

Input: 120

Output: 21

Note:

Assume our The environment can only store 32-bit signed integers, so its value range is [−231, 231 − 1]. Please follow this assumption and return 0 if the integer overflows after inversion.

class Solution {
    /**
     * @param Integer $x
     * @return Integer
     */
    function reverse($x) {
 
        $max = pow(2,31)-1;
        $min = pow(-2,31);
        $strlen = strlen($x);
        if($x >=0){
            $num = (int)strrev($x);
        }else{
            $num = '-'.(int)strrev(trim($x,'-'));
        }
        if($min  < $num && $num < $max){
            return $num;
        }else{
            return 0;
        }
    }
}

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