LeetCode 9. Palindrome Number迴文數
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.
解法一：
class Solution {
public:
bool isPalindrome(int x) {
if(x<0)
return false;
else
{
int d=1;
while(x/d>=10)
d=d*10;
while(x)
{
int m=x/d;
int n=x%10;
if(m!=n)
return false;
x=x%d/10;
d=d/100;
}
return true;
}
}
};
解法二：
class Solution
{
public:
bool isPalindrome(int x) {
if(x<0|| (x!=0 &&x%10==0)) return false;
int sum=0;
while(x>sum)
{
sum = sum*10+x%10; x = x/10;
}
return (x==sum)||(x==sum/10);
}
};