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?
找回文数。要求不转化成字符串。
思路:
1.负数都不是
2.0是
3.将这个数倒序,核心就是取余,取商。不要忘了最后商为0 时还有一个余数要加上。
class Solution {
public:
bool isPalindrome(int x) {
if(x==0)
return true;
if(x<0)
return false;
int remainder = x%10;
int quotient = x/10;
int temp = 0;
while(quotient){
temp=temp*10+remainder;
remainder = quotient%10;
quotient = quotient/10;
}
temp=temp*10+remainder;
if(temp==x)
return true;
return false;
}
};