cmpsc330hw4/strategic_player.cpp

#include "strategic_player.h"

using namespace std;

void StrategicPlayer::selectLineLocation(Board& board, int& row, int& col) {
    int rows = board.getRows();
    int cols = board.getCols();

    // Step 1: Try to complete a box
    for (int r = 1; r < 2 * rows - 2; r += 2) { // Iterate over box centers (odd rows)
        for (int c = 1; c < 2 * cols - 2; c += 2) { // Iterate over box centers (odd cols)
            // Check adjacent lines for an opportunity to complete a box
            if (board.isLineValid(r - 1, c) && // Top line
                board.get(r + 1, c) != ' ' && // Bottom line
                board.get(r, c - 1) != ' ' && // Left line
                board.get(r, c + 1) != ' ') { // Right line
                row = r - 1;
                col = c;
                return;
            }
            if (board.isLineValid(r + 1, c) && // Bottom line
                board.get(r - 1, c) != ' ' && // Top line
                board.get(r, c - 1) != ' ' && // Left line
                board.get(r, c + 1) != ' ') { // Right line
                row = r + 1;
                col = c;
                return;
            }
            if (board.isLineValid(r, c - 1) && // Left line
                board.get(r - 1, c) != ' ' && // Top line
                board.get(r + 1, c) != ' ' && // Bottom line
                board.get(r, c + 1) != ' ') { // Right line
                row = r;
                col = c - 1;
                return;
            }
            if (board.isLineValid(r, c + 1) && // Right line
                board.get(r - 1, c) != ' ' && // Top line
                board.get(r + 1, c) != ' ' && // Bottom line
                board.get(r, c - 1) != ' ') { // Left line
                row = r;
                col = c + 1;
                return;
            }
        }
    }

//     Step 2: Avoid moves that leave a box with one line remaining
    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 (board.isLineValid(r, c)) {
                // Simulate placing the line
                board.placeLine(r, c, name);

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

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

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

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

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