Palindrome Number
Given an integer x, return true if x is palindrome integer.
An integer is a palindrome when it reads the same backward as forward. For example, 121 is palindrome while 123 is not.
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Example 1:
Input: x = 121
Output: true
Example 2:
Input: x = -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: x = 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.
Example 4:
Input: x = -101
Output: false
Constraints:
-231 <= x <= 231 - 1
C++ Solution
思路是转化为string，然后左右指针对比，一旦有不同就返回false，直到指针相遇。当然负数立马返回false。
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class Solution {
public:
bool isPalindrome(int x) {
if (x < 0) {
return false;
} else {
char tmp[32];
sprintf(tmp, "%d", x);
string str = string(tmp);
int left = 0;
int right = str.length() - 1;
while (left < right) {
if (str[left] != str[right]) {
return false;
}
left++;
right--;
}
}
return true;
}
};
