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?
思路
和第七题十分相似
思路是将一个数倒过来 如果他和原数相等则是palindrome
关键点再如何到过来
class Solution {
public boolean isPalindrome(int x) {
if(x <0){
return false;
}
if(x<10){
return true;
}
int original = x;
int reverse = 0;
while(x!=0){
reverse = reverse *10 + x%10;
x/=10;
}
return reverse == original;
}
}