LeetCode: Reverse Integer

一次过

 1 class Solution {

 2 public:

 3     int reverse(int x) {

 4         // Start typing your C/C++ solution below

 5         // DO NOT write int main() function

 6         bool isNeg = x < 0;

 7         x = abs(x);

 8         int ret = 0;

 9         while (x) {

10             ret = ret * 10 + x % 10;

11             x /= 10;

12         }

13         return isNeg? -ret : ret;

14     }

15 };

 C#

 1 public class Solution {

 2     public int Reverse(int x) {

 3         bool neg = x < 0;

 4         if (x == Int32.MinValue) x = Int32.MaxValue;

 5         else x = Math.Abs(x);

 6         int ans = 0;

 7         while (x > 0) {

 8             if (ans > (Int32.MaxValue - x % 10) / 10) return 0;

 9             ans = ans * 10 + x % 10;

10             x /= 10;

11         }

12         return neg? -ans : ans;

13     }

14 }

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