# All code written by Christopher Chen
print("Welcome to a game of Connect 4")
cur_board = []
height = []
size = 0
while True:
  try:
    size = int(input("Pick your size of board (from 5 to 10)"))
  except:
    continue
  if (size >= 5 and size < 11):
    break
  print("Not Valid")
def make_board():
  for i in range(size):
    height.append(0)
    row = []
    for j in range(size):
      row.append(" ")
    cur_board.append(row)
def print_board(board):
  pr = " "
  for i in range(size):
    pr += str(i + 1)
    pr += " "
  
  for i in range(size):
    string = ""
    string += "|"
    for j in range(size):
      string += str(board[i][j])
      string += "|"
    print(string)
  print(pr)
def check(board):
  for i in range(size):
    for j in range(size - 4 + 1):
      x = 0
      o = 0
      for k in range(4):
        if (board[i][j + k] == "X"):
          x += 1
        if (board[i][j + k] == "O"):
          o += 1
      if (x == 4):
        return "X"
      elif (o == 4):
        return "O"
    
  for i in range(size):
    for j in range(size - 4 + 1):
      x = 0
      o = 0
      for k in range(4):
        if (board[j + k][i] == "X"):
          x += 1
        if (board[j + k][i] == "O"):
          o += 1
      if (x == 4):
        return "X"
      elif (o == 4):
        return "O"
  for i in range(size):
    for j in range(size):
      if (i + 4 > size or j + 4 > size):
        continue
      x = 0
      o = 0
      for k in range(4):
        if (board[i + k][j + k] == "X"):
          x += 1
        if (board[i + k][j + k] == "O"):
          o += 1
      if (x == 4):
        return "X"
      elif (o == 4):
        return "O"
  for i in range(size):
    for j in range(size):
      if (i - 4 < 0 or j + 4 > size):
        continue
      x = 0
      o = 0
      for k in range(4):
        if (board[i - k][j + k] == "X"):
          x += 1
        if (board[i - k][j + k] == "O"):
          o += 1
      if (x == 4):
        return "X"
      elif (o == 4):
        return "O"
  return "None"

make_board()
print_board(cur_board)
checks = 0
while (check(cur_board) == "None"):
  mark = ""
  if (checks % 2 == 0):
    mark = "X"
  else:
    mark = "O"
  print("It is " + mark + "'s turn")
  
  if (checks >= size**2):
    break
  column = 0
  while (True):
    try: 
      column = int(input("Enter a column."))
      if (column < size + 1 and column >= 1 and height[column - 1] < size ):
        break
    except ValueError:
      pass
    print("Not Valid")
  cur_board[size - height[column - 1] -1][column - 1] = mark
  height[column - 1] += 1
  print_board(cur_board)
  checks += 1
print(" ")
print(" ")
if (checks != size ** 2): 
  print(check(cur_board) + " WINS!!!!!!!")
if (checks == size ** 2):
  print("-----Tie!-----")