Given an integer x, return true if x is a palindrome, and false otherwise.
Example 1:
Input: x = 121 Output: true Explanation: 121 reads as 121 from left to right and from right to left.
Example 2:
Input: x = -121 Output: false Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.
Example 3:
Input: x = 10 Output: false Explanation: Reads 01 from right to left. Therefore it is not a palindrome.
Constraints:
-231 <= x <= 231 - 1Follow up: Could you solve it without converting the integer to a string?
class Solution {
public:
bool isPalindrome(int x) {
string s = to_string(x);
for(int i=0; i<s.size()/2; i++)
if(s[i]!=s[s.size()-1-i])
return false;
return true;
}
};class Solution {
public:
bool isPalindrome(int x) {
string s = to_string(x);
for(int i=0; i<s.size()/2; i++)
if(s[i]!=s[s.size()-1-i])
return false;
return true;
}
};class Solution {
public boolean isPalindrome(int x) {
if (x < 0 || x > 0 && x % 10 == 0)
return false;
int rev = 0;
while (x > rev) {
rev = rev * 10 + x % 10;
x /= 10;
}
return (x == rev || x == rev / 10);
}
}