TicTacToe.swift

class TicTacToe {

    var rows: [Int]!
    var cols: [Int]!
    var diagonal: Int!
    var antiDiagonal: Int!
    /** Initialize your data structure here. */
    init(_ n: Int) {
        rows = []
        cols = []
        for i in 0..<n {
            rows.append(0)
            cols.append(0)
        }
        diagonal = 0
        antiDiagonal = 0
    }
    
    /** Player {player} makes a move at ({row}, {col}).
        @param row The row of the board.
        @param col The column of the board.
        @param player The player, can be either 1 or 2.
        @return The current winning condition, can be either:
                0: No one wins.
                1: Player 1 wins.
                2: Player 2 wins. */
    func move(_ row: Int, _ col: Int, _ player: Int) -> Int {
        let toAdd = player == 1 ? 1 : -1
        rows[row] = rows[row] + toAdd
        cols[col] = cols[col] + toAdd
        if row == col {
            diagonal += toAdd
        }

        if col == (cols.count - row - 1){
            antiDiagonal += toAdd
        }
    
        let size = rows.count
        if abs(rows[row]) == size ||
            abs(cols[col]) == size ||
            abs(diagonal) == size  ||
            abs(antiDiagonal) == size {
            return player;
        }
        return 0
    }
}

/**
 * Your TicTacToe object will be instantiated and called as such:
 * let obj = TicTacToe(n)
 * let ret_1: Int = obj.move(row, col, player)
 */