9. Palindrome Number

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1. Java

public class Solution {    public boolean isPalindrome(int x) {        if(x<0) return false;        return x==reverse(x);    }    public int reverse(int x) {        long sum=0;        for(; x!=0; x = x/10){ // can not be x>0, since x can be <0            sum = sum*10 + x%10;            if(sum>Integer.MAX_VALUE || sum<Integer.MIN_VALUE) return 0;        }        return (int) sum;    }}

public class Solution {    public boolean isPalindrome(int x) {        if(x<0) return false;        int len = String.valueOf(Math.abs(x)).length()-1;        while(len>0){            int base = (int) Math.pow(10,len);             if(x/base != x%10) return false;            x = (x%base)/10;            len-=2;         }        return true;    }}

public class Solution {    public boolean isPalindrome(int x) {        if(x<0) return false;        int L = (int)Math.log10(x)+1;        if(L<2) return true;        while(L>=2){            int h = (int)(x/Math.pow(10,L-1));            int t = x%10;            if(h!=t) return false;            x = (int)(x%Math.pow(10,L-1)/10);            L = L-2;        }        return true;    }}

2. Python:

class Solution(object):    def isPalindrome(self, x):        """        :type x: int        :rtype: bool        """        if x<0: return False        base=1        while x/base>9:            base=base*10        while base>9:            if x%10 != x/base:                return False            x=x%base            x=x/10            base=base/100        return True

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