cmpsc330hw5/strategic_player.cxx

#include "strategic_player.h"
#include "common.h"

extern "C" IPlayer* PlayerFactory()
{
    return new StrategicPlayer();
}

// Helper functions
inline int normalize(int x) {
    return (x + 1) >> 1;
}

inline char getPoint(Board &board, const int row, const int col) {
    return board(row, col);
}

inline bool isLineValid(Board &board, const int row, const int col) {
    return (row > -1 && row < board.GetRows() && col > -1 && col < board.GetCols()) &&
           ((row & 1) != (col & 1)) && (getPoint(board, row, col) == ' ');
}

inline void set(Board &board, int r, int c, char ch) {
    board(r, c) = ch;
}
//


string StrategicPlayer::PlayerInfo() {
    return "Sandipsinh Rathod (sdr5549@psu.edu), Sapan Shah (scs6041@psu.edu)";
}

void StrategicPlayer::Init(int board_rows, int board_cols, char box_type, char line_type) {
    this->name = box_type;
    this->box_name = line_type;
    this->board.AllocateBoard(board_rows, board_cols);
}


StrategicPlayer::~StrategicPlayer() {
    board.FreeBoard();
}

void StrategicPlayer::Close() {
    board.FreeBoard();
}

/// TODO: check if we needs checks :)
void StrategicPlayer::EventAddLine(char bar, const Loc &loc) {
    set(board, loc.row, loc.col, bar);
}

void StrategicPlayer::EventAddBox(char box, const Loc &loc) {
    set(board, loc.row, loc.col, box);
}

inline void selectLine(Board &board, int &row, int &col, int rows, int cols, char name) {
    int max_row = 2 * rows - 2;
    int max_col = 2 * cols - 2;
    
    // Step 1: Try to complete a box
#pragma omp parallel for collapse(2)
    for (int r = 1; r < max_row; r += 2) {
        // Iterate over box centers (odd rows)
        for (int c = 1; c < max_col; c += 2) {
            // Iterate over box centers (odd cols)
            // Check adjacent lines for an opportunity to complete a box
            if (isLineValid(board, r - 1, c) && // Top line
                getPoint(board, r + 1, c) != ' ' && // Bottom line
                getPoint(board, r, c - 1) != ' ' && // Left line
                getPoint(board, r, c + 1) != ' ') {
                // Right line
                row = r - 1;
                col = c;
                return;
            }
            if (isLineValid(board, r + 1, c) && // Bottom line
                getPoint(board, r - 1, c) != ' ' && // Top line
                getPoint(board, r, c - 1) != ' ' && // Left line
                getPoint(board, r, c + 1) != ' ') {
                // Right line
                row = r + 1;
                col = c;
                return;
            }
            if (isLineValid(board, r, c - 1) && // Left line
                getPoint(board, r - 1, c) != ' ' && // Top line
                getPoint(board, r + 1, c) != ' ' && // Bottom line
                getPoint(board, r, c + 1) != ' ') {
                // Right line
                row = r;
                col = c - 1;
                return;
            }
            if (isLineValid(board, r, c + 1) && // Right line
                getPoint(board, r - 1, c) != ' ' && // Top line
                getPoint(board, r + 1, c) != ' ' && // Bottom line
                getPoint(board, r, c - 1) != ' ') {
                // Left line
                row = r;
                col = c + 1;
                return;
            }
        }
    }

    //     Step 2: Avoid moves that leave a box with one line remaining
#pragma omp parallel for collapse(2)
    for (int r = 0; r < 2 * rows - 1; ++r) {
        // Iterate over all valid rows
        for (int c = 0; c < 2 * cols - 1; ++c) {
            // Iterate over all valid cols
            if (isLineValid(board, r, c)) {
                // Simulate placing the line
                set(board, r, c, name);

                // Check if this move leaves a box with only one line remaining
                bool createsOpportunity = false;
                for (int nr = 1; nr < max_row; nr += 2) {
                    // Iterate over box centers
                    for (int nc = 1; nc < max_col; nc += 2) {
                        if (getPoint(board, nr, nc) == ' ') {
                            int adjacentLines = 0;
                            if (nr > 0 && getPoint(board, nr - 1, nc) != ' ') adjacentLines++; // Top line
                            if (nr < max_row && getPoint(board, nr + 1, nc) != ' ') adjacentLines++; // Bottom line
                            if (nc > 0 && getPoint(board, nr, nc - 1) != ' ') adjacentLines++; // Left line
                            if (nc < max_col && getPoint(board, nr, nc + 1) != ' ') adjacentLines++; // Right line

                            if (adjacentLines == 3) {
                                // Opponent can complete this box
                                createsOpportunity = true;
                                break;
                            }
                        }
                    }
                    if (createsOpportunity) break;
                }

                set(board, r, c, ' '); // Undo the simulated move

                if (!createsOpportunity) {
                    row = r;
                    col = c;
                    return;
                }
            }
        }
    }

    // Step 3: Fallback to the first valid move
#pragma omp parallel for collapse(2)
    for (int r = 0; r < 2 * rows - 1; ++r) {
        for (int c = 0; c < 2 * cols - 1; ++c) {
            if (isLineValid(board, r, c)) {
                row = r;
                col = c;
                return;
            }
        }
    }
}

Loc StrategicPlayer::SelectLineLocation() {
    int rows = normalize(board.GetRows());
    int cols = normalize(board.GetCols());

    int row, col;
    selectLine(board, row, col, rows, cols, name);

    return Loc(row, col);
}