Combinations from n arrays picking one element from each array

test this

public static void Main()
{
List<int[]> arr = new List<int[]>()
{
new int[] { 11, 12, 13 },
new int[] { 21, 22, 23 },
new int[] { 31, 32, 33 },
new int[] { 41, 42, 43 },
new int[] { 51, 52, 53 },
new int[] { 61, 62, 63 },
new int[] { 71, 72, 73 },
new int[] { 81, 82, 83 },
new int[] { 91, 92, 93 },
new int[] { 111, 112, 113 },
new int[] { 121, 122, 123 },
new int[] { 131, 132, 133 },
};
print(arr);
Console.ReadLine();
}
static void print(List<int[]> arr)
{
// Number of arrays
int n = arr.Count;
// To keep track of next
// element in each of
// the n arrays
int[] indices = new int[n];
// Initialize with first
// element's index
for (int i = 0; i < n; i++)
indices[i] = 0;
while (true)
{
// Print current combination
for (int i = 0; i < n; i++)
Console.Write(arr[i][indices[i]] + " ");
Console.WriteLine();
// Find the rightmost array
// that has more elements
// left after the current
// element in that array
int next = n - 1;
while (next >= 0 &&
((indices[next] + 1) >=
(arr[next].Length)))
next--;
// No such array is found
// so no more combinations left
if (next < 0)
return;
// If found move to next
// element in that array
indices[next]++;
// For all arrays to the right
// of this array current index
// again points to first element
for (int i = next + 1; i < n; i++)
indices[i] = 0;
}
}

1 Reply

Know the answer? Post it — somebody with the same question will find it here.

Sachin Singh5y ago
test this
public static void Main()
{
          List<int[]> arr = new List<int[]>()
          {
              new int[] { 11, 12, 13 },
              new int[] { 21, 22, 23 },
              new int[] { 31, 32, 33 },
              new int[] { 41, 42, 43 },
              new int[] { 51, 52, 53 },
              new int[] { 61, 62, 63 },
              new int[] { 71, 72, 73 },
              new int[] { 81, 82, 83 },
              new int[] { 91, 92, 93 },
              new int[] { 111, 112, 113 },
              new int[] { 121, 122, 123 },
              new int[] { 131, 132, 133 },
      };
          print(arr);
          Console.ReadLine();
      }
      static void print(List<int[]> arr)
      {
          // Number of arrays
          int n = arr.Count;

          // To keep track of next
          // element in each of
          // the n arrays
          int[] indices = new int[n];

          // Initialize with first
          // element's index
          for (int i = 0; i < n; i++)
              indices[i] = 0;

          while (true)
          {
              // Print current combination
              for (int i = 0; i < n; i++)
                  Console.Write(arr[i][indices[i]] + " ");

              Console.WriteLine();

              // Find the rightmost array
              // that has more elements
              // left after the current
              // element in that array
              int next = n - 1;
              while (next >= 0 &&
                  ((indices[next] + 1) >=
                  (arr[next].Length)))
                  next--;

              // No such array is found
              // so no more combinations left
              if (next < 0)
                  return;

              // If found move to next
              // element in that array
              indices[next]++;

              // For all arrays to the right
              // of this array current index
              // again points to first element
              for (int i = next + 1; i < n; i++)
                  indices[i] = 0;
          }
}