spoj#THECODE. Subset with all Digits
Subset with all Digits
Given a list of n d-digit numbers, choose the smallest subset from the list that covers all the digits [0-9].
Input
First line contains a positive integer T representing number of testcases.
Next line contains two numbers n and d, where n is the size of the list and d is number of digits in each number.
Next n lines follow each containing a d digit number made from [0-9]
1 ≤ t ≤ 100
1 ≤ n ≤ 1000
1 ≤ d ≤ 1000
Output
Output the length of the smallest subset that covers all digits [0-9]. Return -1 if not possible.
Example
Input:
2
4 5
01234
56789
01456
13452
4 5
11234
56789
01456
13452
Output:
2
3
Explanation:
Smallest set will be {01234,56789}
Smallest set will be {11234,56789,01456}