9.Palindrome Number

【题目】

Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.

判斷一個整數是否是回文數。回文數是指正序（從左向右）和倒序（從右向左）讀都是一樣的整數。

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.

【思路】

回文數簡單就是左到右，右到左皆相同就是回文數了，

【解法】

☆JAVA

class Solution {
    public boolean isPalindrome(int x) {
        boolean result = false;
        int temp = x;
        int after = 0;
        if(x<0){return result;}
        while(temp != 0){
            after = after * 10 + temp % 10;
            temp = temp / 10;
        }
        if(x == after){result = true;}
        return result;
    }
}

☆Python

class Solution:
    def isPalindrome(self, x):
        boo = False;
        result = x;
        temp = 0;
        if(x<0): return boo;
        while(result != 0):
            temp = temp * 10 + result % 10;
            result = result // 10;
        if(temp == x):
            boo = True;
        return boo;

當然還有之前第七題學到的反轉陣列，這樣可以輕鬆解決這題

class Solution:
    def isPalindrome(self, x):
        result = str(x)[::-1];
        if(str(x) == result):
            return True
        else: 
            return False;