# Palindrome Number -- solving notes, palindromenumber

Source: Internet
Author: User

Palindrome Number -- solving notes, palindromenumber

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

Click to show spoilers.

Some hints:
Cocould negative integers be palindromes? (Ie,-1)

If you are thinking of converting the integer to string, note the restriction of using extra space.

You cocould also try reversing an integer. However, if you have solved the problem "Reverse Integer", you know that the reversed integer might overflow. How wocould you handle such case?

There is a more generic way of solving this problem.

Solution: Split the number of int types one by one, put all elements in a vector, and then determine whether the vector is symmetric between the left and right.

Note: Use push_back to add elements in a vector. Use the following table to retrieve the number of elements in a vector.

The Code is as follows:

`Class Solution {public: bool isPalindrome (int x) {if (x <0) return false; vector <int> nums; while (x) {nums. push_back (x % 10); x/= 10;} int len = nums. size (); for (int I = 0; I <len/2; I ++) {if (nums [I]! = Nums [len-1-I]) % subscript pay attention to return false;} return true ;}};`

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