As told by Wikipedia, “The Eight Queens puzzle algorithms the issue of putting eight chess sovereigns on an 8×8 chessboard so no two sovereigns assault one another. In this way, an answer necessitates that no two sovereigns share a similar line, section, or corner to corner.”
f it’s not too much trouble, attempt this yourself, and track down a couple of more arrangements by hand.
We’d prefer to compose a program to discover answers to this riddle. Truth be told, the riddle sums up to putting N sovereigns on an NxN board, so we will consider the overall case, not simply the 8×8 case. Maybe we can discover answers for 12 sovereigns on a 12×12 board or 20 sovereigns on a 20×20 board.
Topic of post
So, I am building an encounter for an upcoming game, and I want to incorporate a puzzle from an old adventure called "Crypt of Lyzandred the Mad". The basic premise of the puzzle is that the players find themselves in a life-sized chessboard with the only chess pieces being 8 different queens. There is a plaque that explains that they need to arrange the Queens so that they can't attack one another. I don't want to overstep copy write stuff, so I just attached a partial screenshot with only the description here.
What I would like to do is add a little extra layer to the puzzle. Instead of the plaque outright telling them what they need to do, I would like to use a riddle instead, ideally the riddle should give hints to some of the details listed in the description, such as the queens turning on the player, or the gauntlets slowing them down, etc.
Some kind of fun/mysterious riddle would be super helpful, even if it was just a starting place for me to work with. Riddles are my DM kryptonite, help!
Apparently this came up and I have no idea how to even begin. I tried a few brute force techniques on the paper, without any thinking applied, and ended up placing only 7 queens at most.
What is the missing logic here?
Also what can I do to improve such skills?
http://en.wikipedia.org/wiki/Eight_queens_puzzle
How do I set up decision variables with feasibility constraints? I'm trying to figure out how to approach this with linear programming. Thank you for your help guys!
My program runs but outputs
|0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0||0|
which doesn't solve the puzzle. Any tips or advice would be much appreciated.
Edit: The problem seems to arise from the index method (which is currently a work in progress).
public class Queens {
public static final int BOARD_SIZE = 8;
public static final int EMPTY = 0;
public static final int QUEEN = 1;
private int board[][];
public Queens() {
board = new int[BOARD_SIZE][BOARD_SIZE];
}
public void clearBoard() {
for (int i = 0; i < 8; i++) {
for (int j = 0; j < 8; j++) {
board[i][j] = 0;
}
}
}
public void displayBoard() {
for (int[] board1 : board) {
for (int i = 0; i < board.length; i++) {
if (board1[i] == 1) {
System.out.print("|1|");
} else {
System.out.print("|0|");
}
}
}
}
public boolean placeQueens(int column) {
if (column > BOARD_SIZE) {
return true;
} else {
boolean queenPlaced = false;
int row = 1;
while (!queenPlaced && row <= BOARD_SIZE) {
if (isUnderAttack(row, column)) {
row++;
} else {
setQueen(row, column);
queenPlaced = placeQueens(column + 1);
if (!queenPlaced) {
removeQueen(row, column);
row++;
}
}
}
return queenPlaced;
}
}
private void setQueen(int row, int column) {
row = index(row);
column = index(column);
board[row][column] = QUEEN;
}
private void removeQueen(int row, int column) {
for (int i = 0; i < 8; i++)
{
if (board[i][column] == 1)
{
board[i][column] = 0;
i = 8;
}
}
}
private boolean isUnderAttack(int row, int column) {
{
for (int i = 0; i < BOARD_SIZE; i++) {
if (board[row][i] == QUEEN)
return true;
int j = row - column + i;
if (0 <= j && j <
As the title says, I want to practise checkmating with a king and queen vs a sole king, a quick look through the puzzles on chess.com and I can’t find a category for that - is there a dedicated category or does it fall under a larger checkmate category of puzzles?
Link when video finishes processing.
I implemented 8 queens puzzle from the book SICP exercise 2.42. queens function takes board size as an argument and returns solutions to the problem as a list. it works great until 7 queens but after 7 queens it throws max recursion depth error. Why is this error throwed exactly after 7 queens ? Here's the code:
def accumulate (op,init,seqs):
if not seqs:
return init
else:
return op (car(seqs),accumulate(op,init,(cdr(seqs))))
def enumerate_interval (low,high):
if low > high:
return []
else:
return [low] + enumerate_interval ((low+1),high)
def car (l):
return l[0]
def cdr (l):
return l[1:]
def cadr (l):
return car(cdr(l))
def cons (x,y):
return [x] + y
def append (x,y):
return x + y
def flatmap (proc,seq):
return accumulate (append,[],list(map(proc,seq)))
def filter (predicate,seq):
if not seq:
return []
elif predicate(car(seq)):
return cons(car(seq),filter(predicate,cdr(seq)))
else:
return filter(predicate,cdr(seq))
def make_position (row,col):
return (row,col)
def row_position (position):
return car(position)
def col_position (position):
return cadr(position)
def adjoin_position (row,col,positions):
return append (positions,[make_position(row,col)])
def safe (k,positions):
index = 0
while index < len(positions):
row_var = row_position(positions[index])
col_var = col_position(positions[index])
for i in positions[index+1:]:
if row_var == row_position(i):
return False
elif abs(row_var-row_position(i)) == abs(col_var-col_position(i)):
return False
else:
continue
index += 1
return True
def queens (board_size):
def queen_cols (k):
if k == 0:
return [[]]
else:
return filter(lambda positions:(safe(k,positions)),flatmap(lambda rest_of_queens:list(map(lambda new_row:adjoin_position(new_row,k,rest_of_queens),enumerate_interval (1,board_size))),queen_cols(k-1)))
return queen_cols(board_size)
Hi there!
Let's do one more puzzle and with this one we'll change the rules a bit.
Instead posting solutions here in the comments section, please send me them via PM (not chat, since I rarely check it) with "Puzzle #11" in the title. After 24 hours, I'll randomly draw the winner who'll receive a cosmetic bundle of their choice, purchasable by Meteorite Powder.
Additionally, the author of the first correct solution will receive a piece of a different kind of puzzle, provided by Ryan, to post here on r/gwent. EDIT: Congrats to /u/AltMarina! Artwork piece can be seen here.
With all that out of the way, let's go to the puzzle.
This one was originally made few months ago, for GabbyDigs, who solved a bunch of my puzzles on her stream, but since it's one of my favourite puzzles, I have to share it more.
The goal is to end the puzzle with Endrega Queen on your side of the board.
And here's the starting board.
Hope you'll enjoy it, and if you'd like to check the previous puzzles, you can do so right here.
Cheers
I've recently finished a rewatch of I, Borg and the events of the episode got be thinking about the Borg Queen and her role in the collective (I know it's been done to death, but hear me out).
One of the main sticking points fans have with the Queen is that her role in the collective seems to contradict the previously established dynamics from TNG. Given that the collective is essentially just the combined memories, experiences and thoughts of everyone who has been assimilated, the entire idea of an "individual" just seems kind of silly (Locutus is arguably the real issue, but he seems to get less heat from the fans).
That being said, First Contact is an otherwise great film with a couple of glaring plot holes/inconsistencies so hopefully this explanation helps make it slightly more palatable to the fans who really can't get passed the concept of the Queen.
I, Borg and the "unsolvable puzzle"
During the events of I, Borg, the Enterprise finds a Borg who has been disconnected from the collective (Hugh). Everyone knows what goes down after that, but one scene in particular has always stood out to me; Data proposes using Hugh to introduce a "virus" of sorts into the collective, however it's not a standard computer virus, but rather an impossible puzzle of sorts that takes advantage of the Borg's single-mindedness and collective processing/sorting of new information.
The virus is described as an infinitely expanding, abstract puzzle that continually adjusts and changes as it is "solved" (side note: ideas like this are why I love TNG). Because it cannot be solved, it essentially ties up the processing power of the entire collective, effectively ensuring they will no longer be able to function.
As we all know, the puzzle is never actually deployed due to the ethical implications of using Hugh in such a way. Instead Hugh is just returned to the collective.
It's always struck me as odd that the Borg could be disabled in such a way though. Obviously the idea is clever and creative (the latter of which isn't really in the collective's wheelhouse) but it still feels like a glaring problem with the collective that they could be destroyed by such a simple solution.
Then I got to thinking about the Queen. We don't see the Queen until First Contact (despite that film retroactively confirming that she's present during the events of BoBW - I'll get to that) which obviously takes place after the events of I, Borg. So my theory is:
**The Borg Queen was created
... keep reading on reddit ➡
