1.描述

Reverse digits of an integer.

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

2.分析

3.代码

int reverse(int x) {
    if (0 == x) return 0;
    bool sign = x > 0 ? true : false;
    long long r = 0;
    long long t = x;
    t = t > 0 ? t : -t;
    for (;t;t/=10) {
        r = r * 10 + t % 10;
    }
    
    if (sign && r > 2147483647 || !sign && r > 2147483648)
        return 0;

    return sign ? (int)r : (int)(-r);
}