Leet code (Reverse Integer)
7. Reverse Integer Given a signed 32-bit integer x , return x with its digits reversed . If reversing x causes the value to go outside the signed 32-bit integer range [-2 31 , 2 31 - 1] , then return 0 . Assume the environment does not allow you to store 64-bit integers (signed or unsigned). Example 1: Input: x = 123 Output: 321 Example 2: Input: x = -123 Output: -321 Example 3: Input: x = 120 Output: 21 Example 4: Input: x = 0 Output: 0 Constraints: -2 31 <= x <= 2 31 - 1 Solution class Solution { public: int reverse(int x) { int rev = 0; while (x) { int pop = x % 10; x /= 10; if (rev > INT_MAX/10 || (rev == INT_MAX / 10 && pop > 7)) return 0; if (rev < INT_MIN/10 || (rev == INT_MIN / 10 && pop < -8)) return 0; rev = rev * 10 + pop; } return rev; } };