7.Reverse Integer

7.Reverse Integer
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
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.
talk less, show the code:
class Solution {
int reverse(int x) {
string s=to_string(x);
int flag=(s[0]=='-');
long int res=0;
for(int i=s.length()-1;i>=flag;i--)
res= res*10 + int(s[i]-'0');
return res>INT_MAX ? 0 : (flag? -res: res);
执行用时 :4 ms, 在所有 C++ 提交中击败了87.79%的用户 内存消耗 :8.3 MB, 在所有 C++ 提交中击败了77.33%的用户