7.Reverse Integer

7.Reverse Integer

难度:Easy

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.

talk less, show the code:

class Solution {
public:
    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