每日一练之Reverse Integer[LeetCode No.7]-翻转整数

Reverse digits of an integer.

Example1: x = 123, return 321
Example2: x = -123, return -321

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Note:

The input is assumed to be a 32-bit signed integer. Your function should return 0 when the reversed integer overflows.

注意读入和返回的数都是 int 型的，这时就要考虑反转后这个数会不会超 int，超的话就返回 0 。这时处理数时最好用比 int 大的类型，不然恐怕会超范围。

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;
    }
};