Reverse digits of an integer.
Example1: x = 123, return 321
Example2: x = -123, return -321
Example2: x = -123, return -321
把一个整数reverse,需要考虑两点:1. 判断数的正负 2. 反转是否会溢出。对于第二点,我用long作为函数类型,这样排除了溢出的可能性。
public class Solution { //Time: O(num of digits in x) Space: O(1) public long reverse(int x) { boolean isNeg = false; if (x < 0) { x = -x; isNeg = true; } long res = 0; while (x > 0) { res = res * 10 + x % 10; x /= 10; } if (isNeg) { res = -res; } return res; } }
No comments:
Post a Comment