Questions tagged [game]

A puzzle that asks for determining the winner in a multi-player game.

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7
votes
4answers
535 views

Removing green marbles from the table

Alice and Bob play the following game that starts with $N\ge3$ green marbles on the table. Alice and Bob move alternatingly. Alice makes the first move. In this first move, Alice removes $x$ green ...
9
votes
1answer
367 views

99 numbers on the blackboard

The numbers 1,2,3, ..., 99 are written on the blackboard. Alice and Bob play the following game, taking turns. Alice starts. At every turn, each player removes one number until two numbers are ...
0
votes
0answers
198 views

A Logician's Game of UNO Flip

Two players are in the middle of an ongoing one-on-one game of UNO Flip, with all its standard rules in effect. Play is currently Light Side Up. It is Player B's turn. Player A has 3 cards remaining, ...
3
votes
2answers
799 views

Unsolvable sudoku net with maximum blocks

Definitions For a $9\times9$ grid $G$ (not necessarily respecting sudoku rules), a subset of cells $S$ is defined to be sudoku-friendly if the values in $S$ do not contradict the rules of sudoku. ...
3
votes
3answers
4k views

Lock code game puzzle

I'm trying to solve a lock 3 code game, Can You Crack The Code. From time to time I find myself presented with a puzzle that has 2 possible solutions, but the game only allows one correct answer. For ...
5
votes
5answers
434 views

Russian roulette

You are challenged to a game of Russian roulette. Your opponent places two bullets side by side in a six chamber revolver and spins the chamber. She explains that the game is single turn-based and ...
8
votes
2answers
540 views

How many people are there?

This is a variation of an old puzzle. The game starts with several people sitting in a circle, everyone facing the back of another person. They are all wearing blind folds, so nobody can see anyone ...
16
votes
1answer
343 views

Masyu-making game

Two players are playing a game on a $4\times4$ board. The players take turns adding either a white circle or a black circle into any empty square, so that the board makes a solvable masyu puzzle (with ...
23
votes
11answers
10k views

The 100 soldier problem

I saw this problem many years ago. I am sure many puzzlers will know its original name. I was reminded of it when reading about Conquering of Regions problem. A Strategy Game Involving Conquering of ...
17
votes
1answer
1k views

Clear board in Othello (Generalisation)

Based on Clear board in Othello If we have an $2m\times 2n$ Othello board ($m\geq n\geq 2$), and the centre $4$ squares have the usual starting position, then for what all values of $m$ and $n$ ...
10
votes
1answer
896 views

Clear board in Othello

Is there a valid set of moves in Othello that allows a win score of 64-0 for either player? And is there record of any such game in the past?
7
votes
2answers
281 views

Marbles on a Mancala Board

I would like to introduce an ancient African board game I've just invented. Until someone comes up with a better name, it's called Marble Mancala. The rules are pretty simple: There are two ...
2
votes
1answer
333 views

Master and Slave versus Bob: hard version

Continuation of: "Sub-puzzle: Master and Slave versus Bob the Violent but Honest Psychopath" and "Master and Slave versus Bob: easy version" The hard version is identical to the easy version (see ...
7
votes
2answers
379 views

Alice and Bob play at cards

To pass the time Alice and Bob play a simple game of chance where cards are drawn in pairs from a shuffled standard 52-card deck. If two red cards are drawn Alice wins the round. If two black cards ...
6
votes
2answers
147 views

Positioning cards labeled with numbers from 0-9

Ann and Bob play a game. On a table there are 10 cards which are labeled with number from 0 to 9 each. Bob is allowed to change the position of the cards with a sequence of his preference. When he is ...
7
votes
1answer
252 views

Game Night at the Binomial Elks Club

The Binomial Elks Club, being predominantly composed of ambitious and competitive personalities, often held game nights in which members enjoyed battling each other for high stakes and bragging rights....
5
votes
2answers
124 views

A pile of chips involving powers of 2

Ann and Bob play alternately on a pile of chips. On each play, any number of chips, which is a power of 2 (including 1=$2^0$), can be removed from the pile. Obviously the number of chips to be removed ...
6
votes
1answer
175 views

A pile of chips involving primes

Ann and Bob play alternately on a pile of chips. On each play, either 1, 2 or 3 chips can be removed except if the number of chips is a prime number. In that case either 1, 2, 3, 4 or 5 chips can be ...
10
votes
1answer
289 views

Reverse dots and boxes – Guess the last move

Alice and Bob are playing a game of reverse dots and boxes. The players take turns adding one horizontal or vertical line of size 1 in one free spot on the grid (marked with light gray lines ...
3
votes
1answer
352 views

Need help with an online puzzle / riddle

I found this online riddle at m4tr1x.ws, but now I am stuck. It seems you need to gain deeper and deeper access to this virtual Matrix-style computer system. First you need to create an account via ...
12
votes
1answer
666 views

Reverse dots and… cubes? - Snowflake edition

A Reverse dots-and-boxes puzzle inspired by @jafe Albert and Robinson are playing a game of reverse dots and boxes. The players take turns adding one plane in one free spot on the grid (...
8
votes
2answers
717 views

Reverse dots and boxes, swastika edition

Alistair and Roberta are playing a game of reverse dots and boxes. The players take turns adding one horizontal or vertical line in one free spot on the grid (marked with light gray lines in ...
16
votes
3answers
1k views

The maximum number of SETs with six cards

The SET game works with a deck of $81$ cards. Each card contains a set of symbols with four attributes: color (red, green, purple), shading (empty, striped, or solid), shape (oval, squiggle, or ...
14
votes
2answers
708 views

Reverse dots and boxes

Alice and Bob are playing a game of reverse dots and boxes. The rules are simple: The players take turns adding one horizontal or vertical line in one free spot on the grid (marked with light ...
4
votes
1answer
249 views

Tactical Domino Placement Game

Alice and Bob take turns to place regular dominoes into a $7\times8$ board. The first player who cannot go loses. Is there a winning strategy for either player? Note that in this version the pips on ...
15
votes
3answers
2k views

Optimal play for 2 by 2 dots and boxes

Consider the classic pencil and paper game Dots and Boxes . You can assume the 2 by 2 version (that is with 9 dots). Starting with an empty grid of dots, players take turns, adding a single ...
6
votes
1answer
220 views

I'm a Proper Divisor

Ann and Bob are playing a number game. Ann starts with the number 60. Then she subtracts a proper divisor of 60 from it. Bob then takes the number Ann made and subtracts one of its proper divisors ...
21
votes
3answers
7k views

Knight on a 5 by 5 board

Alice and Bob play a game with a $5\times 5$ chessboard, and a chess knight. Alice begins by placing the knight somewhere on the board. Then, starting with Bob, the players alternate moving the knight ...
6
votes
3answers
452 views

Guessing a number with 250 divisors

Alice and Bob play the following number guessing game. First Alice picks an integer $n$ with exactly $250$ positive divisors. These divisors include $1$ and $n$, and are denoted as $1=d_1<d_2<...
8
votes
1answer
293 views

No point shuffling, just pick your cards

Alice and Bob are playing a card game with the following rules: Alice selects two piles of 3 cards from a standard 52-card deck and places the piles in front of her, face up. Bob can see these ...
10
votes
1answer
308 views

Birthday girl's casino game

My daughter's birthday is coming up. Here's a fun party game we can play to celebrate. (Bring your wallet!) I have a pair of 6-sided dice, and a standard deck of 52 cards. You place your ...
8
votes
3answers
366 views

Four-in-a-line Puzzle

Disclaimer: This is an open-problem, I don't have a complete solution for this puzzle yet. We are playing a $2$-player game: you as a challenger and me as a judge. Initially, there is an empty ...
8
votes
3answers
650 views

Double or Take game

Double or Take is a two-player number game. Alice starts by selecting any positive integer. Bob's options are to: subtract a positive perfect square subtract a positive perfect cube, or double the ...
3
votes
1answer
445 views

The Sphinx puzzle - Heroes of might and magic II

What is the answer? The Sphinx asks you the following riddle: I'm a brook that continues, an old woman or two, when misspelled I'm a trinket, do I confuse you? I'm inane at each moment, ...
36
votes
5answers
11k views

What is the optimal first move in tic-tac-toe?

I have been told that it is possible to guarantee no worse than a tie in normal 3x3 tic-tac-toe, but that the first move is very important. What is that important first move?
21
votes
6answers
2k views

A game with 52 cards

Alice and Bob play the following game with two (identical) standard decks of $52$ cards. First Alice secretly arranges one deck of $52$ cards in a long row on the table. All cards are face-down, and ...
7
votes
3answers
408 views

Writing differences on a blackboard

The numbers 25 and 36 are written on a blackboard. At each turn, a player writes on the blackboard the (positive) difference between two numbers already on the blackboard, if this number does not ...
4
votes
1answer
422 views

Is it Basic Physics?

Which number is next in the sequence? 1, 2, 3, 4, 5, 6, 7, 9, 10 ,11 ,12 ,13 ,14 ,15 ... Describe why and how your answer applies to the given problem.
9
votes
5answers
1k views

How long will my money last at roulette?

I'm at the casino, standing next to a roulette table with a \$10 minimum bet. I want to stay here as long as possible, so I'm going to repeatedly make the minimum bet until I run out of money. I'm ...
32
votes
10answers
3k views

Variant of lion and 100 zebras

Note: This problem remains unsolved, as of 4 Feb 2018, so do try it out This a variation of this question by @Gamow Suppose there are $100$ lions and $100$ zebras. The lions function together as a ...
10
votes
3answers
796 views

Greedy Chocolate Eaters

Alicia and Bobby play a game with a rectangular chocolate bar, scored into an $m$ by $n$ grid of squares. The children alternate turns, with Alicia going first. On a child's turn, they must break ...
0
votes
1answer
93 views

A short nim game [duplicate]

There are 50 lucifers on the table. The rules are: -You must take 1, 2, 3, 4, or 5 lucifers each turn. -After player 1 has taken some amount of lucifers, it is player 2's turn, and vice versa. -...
4
votes
3answers
252 views

Praser 5 - Help

What is the answer to the Griffon's riddle? So tired of beating my head against this one. I've solved the Sphinx, Unicorn, and Pegasus, but this one is killing me. ...
13
votes
3answers
1k views

Spider and fly on a cube

A spider and a fly play a game with a cube of side length $s=1$ and with a positive real number $d$. First, the spider picks its starting point $S$ somewhere on the surface of the cube. Then the fly ...
4
votes
1answer
533 views

Generalisation of Nim

I'm asking for a general formula/algorithm that can be used in such a game. There are $n$ piles, with varying number of pebbles. The number of pebbles in each pile is given by an array from $pile[...
3
votes
1answer
282 views

Another variation of the game of Nim

Two players set several piles of chips. The piles are arranged in a row from left to right. By turns each player takes one chip from one of the piles and adds at will as many chips as he/she wishes (...
5
votes
3answers
225 views

Drawing loops on a sheet of paper

Two people are playing a game, in which each player takes turns drawing closed loops on a sheet of paper. Each new loop must intersect each of the other loops exactly twice. When one player has no ...
10
votes
3answers
653 views

Fight Battle 21

Based off a very, very well-known puzzle The new RPG, Fight Battle 21, is now here! Now with the same three characters as the previous 20 editions! Knight: 6 HP, 60% chance to deal 3 damage Archer: ...
43
votes
4answers
5k views

Rock, Paper, Scissors and Trump

Alicia and Robert are two high-stakes gamblers who are playing a match of rock-paper-scissors. Each winning throw is worth 10 €, paid by the other player. These players have deep pockets, so matches ...
14
votes
1answer
2k views

Cutting three sticks

Cosmo plays the following (single-player) game with three wooden sticks: He first checks whether he can form a triangle from the three sticks (which means: whether the longest stick is at most as ...

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