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?
- public boolean isPalindrome(int x) {
- int[] nums=new int[32];
- int i=0;
- if(x<0)//负数或 最后一位为0(后半句不严谨,单独0是对称的)
- return false;
- while(x/10>0){
- nums[i]=x%10;
- i++;
- x=x/10;
- }
- nums[i]=x%10;
- int len=0;
- for(i=31;i>=0;i--){
- if(nums[i]>0){
- len=i;//数字位数
- break;
- }
- }
- for(i=0;i<=len/2;i++){
- if(nums[i]!=nums[len-i])
- return false;
- }
- return true;
- }