题目链接
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.
思路:
模拟
class Solution {
public:
int reverse(int x) {
bool flag = 0;
if(x<0) {
x = -x;
flag = 1;
}
long long ans = 0;
while(x) {
ans = ans * 10 + x % 10;
x /= 10;
}
if(flag) {
ans = -ans;
}
if(ans < -(1LL<<31) || ans > (1LL<<31)-1) {
return 0;
}
return ans;
}
};