LeetCode 7: Reverse Integer

最新推荐文章于 2025-12-03 23:35:37 发布

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本文介绍了一种方法来反转32位有符号整数的每一位，并提供了详细的实现代码。考虑到整数范围限制，文章强调了如何处理溢出的情况。

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 {
    public int reverse(int x) {
        if(x == 0)return 0;
        int rev = 0;
        if(x > 0) {
			while(x > 0) {
                if(rev >= 0x7fffffff/10.0)return 0;
				rev = rev*10 + x%10;
				x = x/10;         
			}		
        }else {
			while(x < 0) {
                if(rev < 0x80000000/10.0)return 0;
				rev = rev*10 + x%10;
				x = x/10;         
			}		
        }
        return rev;     
    }
}