Cozy Python iterative solution

  • 0

    You can change the markEdgeOArea function to recursive, but will result in Max Recursion Depth Exceeded

    class Solution:
        # @param board, a 2D array
        # Capture all regions by modifying the input board in-place.
        # Do not return any value.
        # 2:37
        def solve(self, board):
            if not board or not board[0]:
            rowLength = len(board)
            colLength = len(board[0])
            # convert to real matrix to make life easier ...
            for row in range(rowLength):
                board[row] = list(board[row])
            for i in range(colLength):
                self.markEdgeOArea(board, 0, i)
                self.markEdgeOArea(board, rowLength - 1, i)
            for j in range(rowLength):
                self.markEdgeOArea(board, j, 0)
                self.markEdgeOArea(board, j, colLength - 1)
            for i in range(rowLength):
                for j in range(colLength):
                    if board[i][j] == 'O':
                        board[i][j] = 'X'
                    if board[i][j] == 'K':
                        board[i][j] = 'O'
        def markEdgeOArea(self, board, i, j):
            queue = collections.deque([(i, j)])
            while queue:
                row, col = queue.popleft()
                if row < 0 or row >= len(board) or col < 0 or col >= len(board[0]) or board[row][col] != 'O':
                board[row][col] = 'K'
                queue.append((row - 1, col))
                queue.append((row + 1, col))
                queue.append((row, col - 1))
                queue.append((row, col + 1))

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