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1958. Check if Move is Legal 👎

  • Time: $O(1)$
  • Space: $O(1)$
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class Solution {
 public:
  bool checkMove(vector<vector<char>>& board, int rMove, int cMove,
                 char color) {
    const vector<pair<int, int>> dirs{{-1, -1}, {-1, 0}, {-1, 1}, {0, -1},
                                      {0, 1},   {1, -1}, {1, 0},  {1, 1}};

    for (const auto& [dx, dy] : dirs) {
      int cellsCount = 2;
      int i = rMove + dx;
      int j = cMove + dy;
      while (0 <= i && i < 8 && 0 <= j && j < 8) {
        // No free cells in between.
        if (board[i][j] == '.')
          break;
        // Need >= 3 cells.
        if (cellsCount == 2 && board[i][j] == color)
          break;
        // >= 3 cells.
        if (board[i][j] == color)
          return true;
        i += dx;
        j += dy;
        ++cellsCount;
      }
    }

    return false;
  }
};

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class Solution {
  public boolean checkMove(char[][] board, int rMove, int cMove, char color) {
    final int[][] dirs = {{-1, -1}, {-1, 0}, {-1, 1}, {0, -1}, {0, 1}, {1, -1}, {1, 0}, {1, 1}};

    for (int k = 0; k < 8; ++k) {
      final int dx = dirs[k][0];
      final int dy = dirs[k][1];
      int cellsCount = 2;
      int i = rMove + dx;
      int j = cMove + dy;
      while (0 <= i && i < 8 && 0 <= j && j < 8) {
        // No free cells in between.
        if (board[i][j] == '.')
          break;
        // Need >= 3 cells.
        if (cellsCount == 2 && board[i][j] == color)
          break;
        // >= 3 cells.
        if (board[i][j] == color)
          return true;
        i += dx;
        j += dy;
        ++cellsCount;
      }
    }

    return false;
  }
}

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class Solution:
  def checkMove(self, board: List[List[str]], rMove: int, cMove: int, color: str) -> bool:
    dirs = [(-1, -1), (-1, 0), (-1, 1), (0, -1),
            (0, 1), (1, -1), (1, 0), (1, 1)]

    for dx, dy in dirs:
      cellsCount = 2
      i = rMove + dx
      j = cMove + dy
      while 0 <= i < 8 and 0 <= j < 8:
        # No free cells in between.
        if board[i][j] == '.':
          break
        # Need >= 3 cells.
        if cellsCount == 2 and board[i][j] == color:
          break
        # >= 3 cells.
        if board[i][j] == color:
          return True
        i += dx
        j += dy
        cellsCount += 1

    return False