LeetCode 728. Self Dividing Numbers

A self-dividing number is a number that is divisible by every digit it contains.

For example, 128 is a self-dividing number because 128 % 1 == 0, 128 % 2 == 0, and 128 % 8 == 0.

Also, a self-dividing number is not allowed to contain the digit zero.

Given a lower and upper number bound, output a list of every possible self dividing number, including the bounds if possible.

Example 1:

Input: 
left = 1, right = 22
Output: [1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 15, 22]

 

Note:

• The boundaries of each input argument are 1 <= left <= right <= 10000.

 

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题目标签：Math

 

　　题目给了我们一个范围，让我们找到范围里面所有的 self-dividing number 加入 ArrayList 返回。

 

　　遍历每一个数字，利用 % 10 拿到digit，检查它是否是0，是否能被 数字整除；再利用 / 10 来去除掉这个digit。

　　

 

 

 

Java Solution:

Runtime beats 42.86% 

完成日期：02/16/2018

关键词：Math

关键点：% 10 拿到digit；/ 10 去除digit

class Solution 
{
    public List<Integer> selfDividingNumbers(int left, int right) 
    {
        List<Integer> res = new ArrayList<>();
        
        for(int i=left; i<=right; i++) // iterate each number
        {
            boolean sd = true;
            int num = i;
            
            while(num > 0) // check whether this number is self-dividing number
            {
                int digit = num % 10;
                
                if(digit == 0 || i % digit != 0)
                {
                    sd = false;
                    break;
                }
                
                num /= 10;
            }
            
            if(sd)
                res.add(i);
        }
        
        return res;
    }
}

参考资料：n/a

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