【回文串2】LeetCode 9. Palindrome Number

LeetCode 9. Palindrome Number

Solution1:我的答案
思路一：转化为字符串

class Solution {
public:
    bool isPalindrome(int x) {
        string x_str = to_string(x);
        int n = x_str.size(), left = 0, right = x_str.size() - 1;
        while (left < right) {
            if (x_str[left] != x_str[right])
                return false;
            else {
                left++; 
                right--;
            }
        }
        return true;
    }
};

思路二：求其逆数比是否相等

class Solution {
public:
    bool isPalindrome(int x) {
        if (x < 0) return false;
        int res = 0, x_copy = x;
        while (x_copy) {
            res = res * 10 + x_copy % 10;
            x_copy /= 10;
        }
        if (res != x)
            return false;
        else
            return true;
    }
};