Submission #1697588

---

Source Code Expand

import Foundation

func isAvailable(x x: Int, y: Int, onBoard board: [[String]]) -> Bool {
    for i in 0..<8 {
        if board[y][i] == "Q" || board[i][x] == "Q" {
            return false
        }
        let y1 = i - x + y
        if 0..<8 ~= y1 && board[y1][i] == "Q" {
            return false
        }
        let y2 = -i + x + y
        if 0..<8 ~= y2 && board[y2][i] == "Q" {
            return false
        }
    }
    return true
}

func walkBoard(board: [[String]], column: Int) -> Bool {
    if column == 8 {
        board.forEach { print($0.reduce("", combine: +)) }
        return true
    }

    let rows: [Int]
    if let index = board[column].indexOf("Q") {
        rows = [index]
    } else {
        rows = (0..<8).map {$0}.filter { isAvailable(x: $0, y: column, onBoard: board) }
    }

    for row in rows {
        var newBoard = board
        newBoard[column][row] = "Q"
        if walkBoard(newBoard, column: column + 1) {
            return true
        }
    }

    return false
}

var board = (0..<8).map { _ in readLine()!.characters.map(String.init(_:)) }
if !walkBoard(board, column: 0) {
    print("No Answer")
}

Submission Info

Judge Result