Leetcode-9: palindromes

subject

Topic linking

Give you an integer x , If x Is a palindrome integer , return true ; otherwise , return false .

Palindrome number refers to positive order （ From left to right ） Reverse order （ From right to left ） Read all the same integers .

• for example ,121 It's palindrome. , and 123 No .

Example 1：

 Input ：x = 121
 Output ：true

Example 2：

 Input ：x = -121
 Output ：false
 explain ： Read left to right ,  by  -121 .  Read right to left ,  by  121- . So it's not a palindrome number .

Example 3：

 Input ：x = 10
 Output ：false
 explain ： Read right to left ,  by  01 . So it's not a palindrome number .

Problem solving

Method 1 ： Double pointer

class Solution {
    
public:
    bool isPalindrome(int x) {
    
        string s=to_string(x);
        int left=0,right=s.size()-1;
        while(left<right){
    
            if(s[left]!=s[right]) return false;
            left++;
            right--;
        }
        return true;
    }
};