let newBoard = createBoard();

  for (let i = 0; i < COLS; i++) {

    for (let j = 0; j < ROWS; j++) {

      newBoard[i][j] = board[i][j];

    }

  }

  return newBoard;

}

​

function findBestMove(board, player) {

  let bestScore = -Infinity;

  let bestMoves = [];

  for (let n = 0; n < COLS; n++) {

    const newBoard = copyBoard(board);

    if (makeMove(newBoard, n, player)) {

      let score = 0;

      if (checkWin(newBoard, player)) {

        score = Infinity;

      } else if (checkWin(newBoard, player == PLAYER.red ? PLAYER.yellow : PLAYER.red)) {

        score = -Infinity;

      } else {

        score = -search(newBoard, player == PLAYER.red ? PLAYER.yellow : PLAYER.red)

      }

      if (score > bestScore) {

        bestMoves = [n];

        bestScore = score;

      } else if (score == bestScore) {

        bestMoves.push(n);

      }

    }

  }

  return random(bestMoves);

}

​

function search(board, player, depth=4) {

  let bestScore = -Infinity;

  for (let n = 0; n < COLS; n++) {

    const newBoard = copyBoard(board);

    if (makeMove(newBoard, n, player)) {

      let score = 0;

      if (checkWin(newBoard, player)) {

        score = Infinity;

      } else if (checkWin(newBoard, player == PLAYER.red ? PLAYER.yellow : PLAYER.red)) {

        score = -Infinity;

      } else if (depth > 0) {

        score = -search(newBoard, player == PLAYER.red ? PLAYER.yellow : PLAYER.red, depth-1)

      } else {

        score = evaluate(newBoard, player);

      }

      if (score > bestScore) {

        bestScore = score;

      }

    }

  }

  return bestScore;

}

​

function evaluate(board, player) {

  return 0;

}