Submission #1697597

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Source Code Expand

func isAvailable(x x: Int, y: Int, onBoard board: [[String]]) -> Bool {
    for i in 0..<8 {
        if board[y][i] == "Q" {
            return false
        }
        if board[i][x] == "Q" {
            return false
        }
    }
    for xx in 0..<8 {
        let yy = xx - x + y
        if 0..<8 ~= yy && board[yy][xx] == "Q" {
            return false
        }
    }
    for xx in 0..<8 {
        let yy = -xx + x + y
        if 0..<8 ~= yy && board[yy][xx] == "Q" {
            return false
        }
    }
    return true
}

func printBoard(board: [[String]]) {
    board.forEach { print($0.reduce("", combine: +)) }
}

func walkBoard(board: [[String]], y: Int) -> Bool {
    if y == 8 {
        printBoard(board)
        return true
    }

    var availableX = [Int]()
    if let qIndex = board[y].indexOf("Q") {
        availableX = [qIndex]
    } else {
        for x in 0..<8 {
            if isAvailable(x: x, y: y, onBoard: board) {
                availableX.append(x)
            }
        }
    }

    for x in availableX {
        var newBoard = board
        newBoard[y][x] = "Q"
        if walkBoard(newBoard, y: y + 1) {
            return true
        }
    }

    return false
}

var board = [[String]]()
for _ in 0..<8 {
    board.append(readLine()!.characters.map(String.init(_:)))
}

if !walkBoard(board, y: 0) {
    print("No Answer")
}

Submission Info

Judge Result