9. Palindrome Number
Easy
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.
题解：计算倒过来的数是多少，判断两个数是否相等就行
1 class Solution { 2 public: 3 bool isPalindrome(int x) { 4 if(x < 0 ) return false; 5 long long lx = 0,rx = x; 6 while(rx > 0){ 7 lx = lx*10+rx%10; 8 rx /= 10; 9 } 10 if(lx==x) return true; 11 else return false; 12 } 13 };
Runtime: 8 ms, faster than 90.24% of C++ online submissions for Palindrome Number.
Memory Usage: 8.2 MB, less than 74.55% of C++ online submissions for Palindrome Number.