Array combinatoric comparison

Question

Introduction

You may remember sudoku, where there can only be one of each number in each row, column and block of nine. The general idea is that if the array contains but one element, you can submit that as a deterministic solution. If there are already filtered arrays (by rows, columns and 3×3 blocks) the remainder can still be deterministic. Where

• a=[1,2];
• b=[1,3];
• c=[2,3];
• d=[1,2,3,4]

d should be reduced to [4] as it apparently cannot be anything else.

Challenge

Provide a sniplet that compares n arrays. For every X, if only X numbers appear at least once in a set of X arrays, then all those X numbers should be removed from each array not in the set. The elements are integer numbers ranging [1, n].

Winning criterion

Lowest character count.

"I'm too young to die" version

9 arrays at most, 9 elements at most.

Test Cases

[1,2]; [2,3]; [1,3]; [1,2,3,4]
[1,2,3]; [2,3,4]; [1,5,6]; [2,3]; [1,4]; [1,2,3,4,6]

Test outputs

[1,2]; [2,3]; [1,3]; [4]
[1,2,3]; [2,3,4]; [5]; [2,3]; [1,4]; [6]

Answer 1

Pyth: 37 29 28 bytes

um?d|-lHl{sHsmg{kdH-dsHGtyQQ

Input is a list of lists like [[1,2], [2,3], [1,3], [1,2,3,4]]. Try it online: Pyth Compiler/Executor

Explanation:

um?d|-lHl{sHsmg{kdH-dsHGtyQQ
u                          Q  G = input array
u                       tyQQ  For each H in powerset(input):
 m                     G        G = [            ...        for d in G]
  ?d               -dsH             [d if ... else d-sum(H) for d in G] 
     -lHl{sH                        len(H)-len(set(sum(H)))!=0
    |                                     or
            smg{kdH                 sum(d is subset of k for k in H)>0

Answer 2

C# - 231 characters

static int[][] P(int[][]a){var m=a.GetUpperBound(0)+1;var j=0;for(var i=0;i<m;i++){var u=new List<int>();for(j=0;j<=i;j++)u=u.Union(a[j]).ToList();if(u.Count()==m)for(j=0;j<m;j++)if(i!=j)a[i]=a[i].Except(a[j]).ToArray();}return a;}

Ungolfed and harness

using System.Collections.Generic;
using System.Linq;

namespace ArrayCombCompar
{
    class Program
    {
        static void Main(string[] args)
        {
            var testArray1 = new int[][] {
                new int[] {1,2},
                new int[] {2,3},
                new int[] {1,3},
                new int[] {1,2,3,4}
            };
            var testArray2 = new int[][] {
                new int[] {1,2,3},
                new int[] {2,3,4},
                new int[] {1,5,6},
                new int[] {2,3},
                new int[] {1,4},
                new int[] {1,2,3,4,6}
            };
            var result1 = P(testArray1);
            var result2 = P(testArray2);
        } // Put breakpoint here to see results

        static int[][] P(int[][]a)
        {
            var m = a.GetUpperBound(0) + 1;
            var j = 0;
            for (var i = 0; i < m; i++)
            {
                var u = new List<int>();
                for (j = 0; j <= i; j++)
                    u = u.Union(a[j]).ToList();
                if (u.Count() == m)
                    for (j = 0; j < m; j++)
                        if (i != j) a[i] = a[i].Except(a[j]).ToArray();
            }
            return a;
        }

     }
}