Reverse digits of an integer.
Example1: x = 123, return 321
Example2: x = -123, return -321
这题主要是要考虑越界的问题,定义ans 和返回ans 都要考虑、
class Solution { public: int reverse(int x) { long long res = 0; while(x) { res = res*10 + x%10; x /= 10; } return (res<INT_MIN || res>INT_MAX) ? 0 : res; } };