Leek: 7. Integer Inversion

topic:

Given a 32-bit signed integer x, return the result of inverting the numeric portion of x. Returns 0
if the inverted integer exceeds the range [−2 ³¹ , 2 ^{31 − 1] of a 32-bit signed integer.}
Assume the environment does not allow storing 64-bit integers (signed or unsigned).

Example 1:
Input: x = -123
Output: -321

solution:

class Solution {
    
    
    public int reverse(int x) {
    
    
    	// 注意int类型反转后的数值可能超出int的表示范围，所以结果用long来存
        long result = 0;
        while(x != 0){
    
    
        	// 利用取模运算和除法运算进行整数反转
            result = result * 10 + x % 10;
            x = x / 10;
        }
        return (int)result == result ? (int)result : 0;
    }
}