Palindrome Number

Palindrome Number

问题：

Determine whether an integer is a palindrome. Do this without extra space.

思路：

常用的进制遍历方法

while(num != 0)
{
        remian = num % 进制;
        num /= 进制;  
}

我的代码：

public class Solution {
    public boolean isPalindrome(int x) {
        if(x < 0)   return false;
        int reverse = reverse(x);
        return reverse == x;
    }
    public int reverse(int x)
    {
        int rst = 0;
        while(x != 0)
        {
            rst = rst * 10 + x % 10;
            x /= 10;
        }
        return rst;
    }
}

他人代码：

class Solution {
public:
    bool isPalindrome(int x) {
        
        //negative number
        if(x < 0)
            return false;
            
        int len = 1;
        while(x / len >= 10)
            len *= 10;
            
        while(x > 0)    {
            
            //get the head and tail number
            int left = x / len;
            int right = x % 10;
            
            if(left != right)
                return false;
            else    {
                //remove the head and tail number
                x = (x % len) / 10;
                len /= 100;
            }
        }
        

　　

学习之处：

• 常见数字访问方法，while(num != 0) num /= 进制数
• 常用的进制增加方法, num = num * 进制 + some remain