acm/leetcode/9.palindrome-number.cpp

/*
 * @lc app=leetcode id=9 lang=cpp
 *
 * [9] Palindrome Number
 *
 * https://leetcode.com/problems/palindrome-number/description/
 *
 * algorithms
 * Easy (44.86%)
 * Likes:    1620
 * Dislikes: 1373
 * Total Accepted:    674.1K
 * Total Submissions: 1.5M
 * Testcase Example:  '121'
 *
 * 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?
 * 
 */
class Solution
{
public:
    bool isPalindrome(int x)
    {
        char buf[20];
        sprintf(buf, "%d", x);
        for (int i = 0, j = strlen(buf); i < j;)
            if (buf[i++] != buf[--j])
                return false;
        return true;
    }
};