Palindrome Number之Java實現
阿新 • • 發佈:2019-05-13
nat nbsp get example ole 取余 等於 public xpl 一、題目
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? 5、循環將集合中的數取出,求得反轉後的數值;
6、與數值x比較是否相等,如是,則返回true,否則返回false。
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.
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?
二、解題思路
1、此題為判斷一個數值是否是回文數,即將數值反轉後是否等於原數值,如是,則為回文數;
2、先判斷數值x是否小於0,如小於0則返回false;
3、再判斷x是否等於0,如是,則返回true;
4、如上面兩種情況都不符合,則將數值x循環取余取出每一位上的數存入集合中;
6、與數值x比較是否相等,如是,則返回true,否則返回false。
三、代碼實現
public boolean isPalindrome(int x) { if (x < 0) { return false; } else if (x == 0) { return true; } else { int temp = x; int result = 0; List<Integer> list = new ArrayList<Integer>(); while (temp != 0) { list.add(temp % 10); temp = temp / 10; } for (int i = 0; i < list.size(); i++) { result = result + list.get(i) * (int)Math.pow(10, list.size() - 1 - i); } if (result == x) { return true; } else { return false; } } }
Palindrome Number之Java實現