9. Palindrome Number
Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.
Example 1:
Input: 121
Output: true
Example 2:
Input: -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: 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.
Follow up:
Coud you solve it without converting the integer to a string?
class Solution {
public:
bool isPalindrome(int x) {
long long tmp = x;
long long calc = 0;
bool ret = false;
while(x)
{
calc = calc * 10 + x%10;
x = x/10;
}
//cout<<"calc:"<<calc<<endl;
if(calc==tmp && tmp >=0){
ret = true;
//cout<<"true"<<endl;
}
return ret;
}
};
