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 <= 1000
题意：自我分裂数字的定义为：该数字可以被其自身每个数字所整除。
例：128是一个自我分裂数字，因为： 128 % 1 == 0，128 % 2 == 0，128 % 8 == 0.
并且，一个自我分裂数字不允许包含数字0.
给定一个较低的边界，一个较高的边界，输出该范围内的自我分裂数字，该范围包括边界。
方法一：直接根据题意要求进行判断。对当前数字i，判断i能否被其自身的每个数字整除。
public List<Integer> selfDividingNumbers(int left, int right) { List<Integer> list = new ArrayList<>(); for(int i = left; i <= right; i++){ int temp = i; while(temp % 10 != 0){ int n = temp % 10; if(i % n != 0) break; temp /= 10; } if(temp == 0) list.add(i); } return list; }
LeetCode提供的答案：
利用字符与数字关系。将数字转换为字符串，再将字符串转换为字符数组，来判断每个数字
public List<Integer> selfDividingNumbers(int left, int right){ List<Integer> list = new ArrayList<>(); for(int i = left; i <= right; i++){ if(isSelfDividing(i)) list.add(i); } return list; } public boolean isSelfDividing(int n){ for(char c : String.valueOf(n).toCharArray()){ if(c == ‘0‘ || n % (c - ‘0‘) != 0) return false; } return true; }