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: [−231, 231 − 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.
反转整数,如果结果不在整数范围内就返回0。
思路:不断使用取余和取整。
class Solution {
public:
int reverse(int x) {
long tmp = 0;
while (x!=0) {
tmp = tmp * 10 + x % 10;
x = x / 10;
}
if (tmp<INT_MIN || tmp>INT_MAX) {
return 0;
}
return tmp;
}
};