The Big Programming Thread - Page 185

// legalMoves is a vector<vector<int>>
// board is a vector<int> representing all the numbers on the "board"

void generateLegalMoves(int startIndex)
{
       // stop the recursion when you reach the last element of the vector
    while ( startIndex < board.size()  )
    {
        // add the individual number if its less than the max_sum
        if ( board[startIndex] <= maxSum )
        {
            vector<int> temp;
            temp.push_back(1); // indicating only 1 number is used - for later evaluations
            temp.push_back(startIndex); // and its index which will make sense later
            temp.push_back(startIndex);
            legalMoves.push_back(temp); // add it to the vector<vector<int>> for later use
        }

        // find valid sums less than max_sum
        int sum = 0; // reset sum at the start of each call to the function.
        for (int i = startIndex; i + 1 < board.size(); i++)
        {
            sum = board[startIndex] + board[i];
            if (sum <= maxSum)
            {
                vector<int> temp;
                temp.push_back(2); // representing 2 numbers are here for later evaluation
                temp.push_back(startIndex); // grabs index of starting number for later evaluation
                temp.push_back(i); // grabs current index for later evaluation
                legalMoves.push_back(temp);
            }
        }

        startIndex++;
        generateLegalMoves(startIndex); // recursive call to start at the next element
    }
}