using System;
using System.Text;

public static string[] GenerateCombinations(string[] Array1, int[] Array2)
{
    if(Array1 == null) throw new ArgumentNullException("Array1");
    if(Array2 == null) throw new ArgumentNullException("Array2");
    if(Array1.Length != Array2.Length)
        throw new ArgumentException("Must be the same size as Array1.", "Array2");

    if(Array1.Length == 0)
        return new string[0];

    int outputSize = 1;
    var current = new int[Array1.Length];
    for(int i = 0; i < current.Length; ++i)
    {
        if(Array2[i] < 1)
            throw new ArgumentException("Contains invalid values.", "Array2");
        if(Array1[i] == null)
            throw new ArgumentException("Contains null values.", "Array1");
        outputSize *= Array2[i];
        current[i] = 1;
    }

    var result = new string[outputSize];
    for(int i = 0; i < outputSize; ++i)
    {
        var sb = new StringBuilder();
        for(int j = 0; j < current.Length; ++j)
        {
            sb.Append(Array1[j]);
            sb.Append(current[j].ToString());
            if(j != current.Length - 1)
                sb.Append(' ');
        }
        result[i] = sb.ToString();
        int incrementIndex = current.Length - 1;
        while(incrementIndex >= 0 && current[incrementIndex] == Array2[incrementIndex])
        {
                current[incrementIndex] = 1;
                --incrementIndex;
        }
        if(incrementIndex >= 0)
            ++current[incrementIndex];
    }
    return result;
}