Questions tagged [strategy]

A puzzle whose solution is a methodological plan of action for realizing a specific goal.

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6
votes
3answers
225 views

How did the criminals escape from the jail?

There are $72$ criminals in a jail in $8$ cells as shown in the picture above. There are $9$ criminals in each cell. There are $4$ guards. Each of them watch over the $4$ corridors. As there is a door ...
-2
votes
1answer
195 views

The Box of Tic-Tacs

You were kidnapped and had no way of escape. The kidnapper opens the lights, and in front of you is an opened box of Tic-Tacs. He claims that he ate from 0-5 Tic-Tacs, (with 60 from the newly-bought ...
1
vote
1answer
118 views

Catch the fugitive

The fugitive is at the origin. He moves at a speed of 100. You have a guard at every integer coordinate except the origin. A guard's speed is 1. The fugitive and your guards move simultaneously and ...
20
votes
2answers
2k views

Can you survive this infinite zombie attack?

You're surrounded by infinitely many zombies. You're at the origin, and zombies occupy the points $(100i,100j)$ for all integer $i, j$ except the origin, as shown below: You and the zombies move ...
7
votes
3answers
375 views

Can you find and capture a shapeshifter?

A town was invaded by aliens, and some of its residents were kidnapped and replaced by shapeshifters. You're tasked with capturing one of the shapeshifters. Here's the setup: There are 7 residents of ...
2
votes
1answer
66 views

Peg Solitaire variant: from 48 on an 8x8 board

Looking at David Ahl's Basic Computer Games, one of the programs that caught my eye was One Check. It's like Peg Solitaire, which I've figured, but it's on an 8x8 board with the 4x4 inner bit hollowed ...
3
votes
0answers
166 views

One vs many. Can white force a draw?

On an infinite chessboard there's a single white king and N black kings. The nearest black king must be K moves away from the white king. Given N, white dictates the value of (finite) K, then black ...
7
votes
2answers
277 views

Can the fugitive escape?

A fugitive is surrounded by N police officers, with the nearest one at distance 1 away. The fugitive and the officers move alternatively. In a fugitive move, the fugitive can travel no more than a ...
6
votes
2answers
229 views

Judgment-free construction of a playlist

Alice and Bob are planning a long car trip and need to come up with a playlist for it. For any given song, they have one of four opinions on it: "That's, like, my favorite song ever" (love), ...
5
votes
1answer
434 views

Best strategy for stick-taking game

Rules of the game: It's a two player game. Moves will alternate between players. There are N sticks on a table. A value M is defined at the start of the game such that 2 < M <= N. On their turn,...
40
votes
7answers
5k views

Amnesiac in a ring shaped palace

Related: Turn off all lights in a ring-shaped palace Your boss has trapped you inside a ring-shaped palace, and all you know about the palace is that there are some number* of identical rooms, each ...
12
votes
3answers
734 views

Outmaneuver your opponents in the duel

A, B and C are in a three way duel. Starting with A, they rotate in the order of A-B-C, each firing one shot at a time. They stand close to one another, so that each can kill one of the others or ...
5
votes
1answer
293 views

Two players alternately name dates

Two players alternately name dates. The winner is the player who names 31st December, and the starting date is 1st January. If a player names Xst of Y Month, the other player can name the first of the ...
13
votes
2answers
2k views

Three knights searching for a princess in a castle

There is a castle with rooms arranged in a 4x4 square grid. The princess living in the castle sleeps in a different room each night, but always one adjacent to the one in which she slept in the ...
7
votes
3answers
618 views

One truthteller, one liar, and two randoms - least questions to identify?

I have landed on a new planet and there are 4 people there. One of them is a truth teller and they always speak the truth. The other is a liar and they always lie. The other 2 are random and they ...
7
votes
4answers
765 views

Sorting 6 boxes by selecting 3 boxes each time

There are 6 boxes, each containing a distinct number. You can select 3 boxes and the Oracle will tell you which box has the smallest number and which has the largest number of the three selected boxes....
11
votes
6answers
13k views

1 Fake Coin among N Amount of coins

You are given $N$ coins which consists of only $1$ fake coin. You also have a sensitive old-fashioned Pan Balance Scale. You are asked to find the fake coin in totally 5 times weighing on the Pan ...
10
votes
1answer
358 views

What type of puzzle is “Room to Grow”?

I saw this game on Steam. They have a demonstration of the game in video form here, and here's the GIF I generated from that video (that's lower in quality and shortened due to the maximum 2 MB ...
3
votes
2answers
200 views

Determine minimal number of moves to find cells on a square table 10×10 in which a treasure is hidden

In a 10x10 square table, two neigbouring 1x1 cells contain a hidden treasure. John needs to guess these cells. In one move he can choose some cell of the table and can get information whether there is ...
62
votes
8answers
106k views

Twelve balls and a scale

You are given twelve identical-looking balls and a two-sided scale. One of the balls is of a different weight, although you don't know whether it's lighter or heavier. How can you use just three ...
5
votes
1answer
230 views

Playing tic-tac-toe by submitting your moves in advance

Suppose that, instead of playing in your turn, you have to submit in advance, an ordered list of the 9 board positions. Then a computer plays for you by using, whenever it is your turn, the leftmost ...
9
votes
4answers
920 views

How to find the 2021st integer co-prime to 15

I recently saw a puzzle where you were to find the 2021st positive integer co-prime to 15 (it was phrased in terms of a game but this is the mathematical core). I wrote code to find the answer but can’...
1
vote
2answers
326 views

Recover the answers of a test with n yes/no questions

Given a test with 𝑛 yes/no questions, a candidate is able to submit multiple solutions. For a given solution, the candidate gets feedback on the number of correct answers. The goal is to recover the ...
2
votes
3answers
360 views

Two of 18 coins are counterfeit

There are $n=18$ coins, and we know exactly $2$ of them are counterfeit. All counterfeit coins differ from normal coins in weight, but otherwise their weight is not known. They can be heavier or ...
-4
votes
1answer
107 views

How to open the lock from this safe?

The puzzle is as follows: The figure from below shows a lock mechanism used to store sensitive data microfilms from a certain lab. This mechanism is magnetic and consists in numbered buttons which ...
13
votes
1answer
3k views

General strategies for solving metal disentanglement puzzles

(When I talk about metal disentanglement puzzles, I have in mind Hanayama and Tavern puzzles.) As opposed to twisty puzzles - which I can approach by playing with commutators and conjugates as a way ...
1
vote
0answers
76 views

100 boxes, only 50 attempts [duplicate]

There are 100 boxes in the room. In every box there is a note with some number from 1 to 100 (no repetitions).Person A comes into the room and checks all the boxes and notes inside them. He can (doesn'...
52
votes
3answers
6k views

Sliding Bolt Puzzle

You are in a room with two adjacent doors locked by four sliding bolts. The bolts are movable and block only one door at a time; however, you do not know which bolt currently is blocking which door. ...
8
votes
1answer
924 views

Heaps of marbles

Alice and Bob play the following game with two heaps of 10,000 and 20,000 marbles. Alice and Bob move alternatingly. Alice makes the first move. In every move, the active player may (i) either remove ...
16
votes
4answers
5k views

The Mexican Standoff

There are three cowboys in a Mexican standoff against each other, named Juan, José, and Jorge. Juan is the straightest shooter in the West, and can hit his target 100% of the time. José, who has a ...
17
votes
9answers
4k views

Solitaire Chess

A friend of mine got me Solitaire Chess for Christmas years ago. I set up the board below. Is it possible to solve it? If so, what is the solution? (No programs allowed- Use only your brain.) Rules: ...
7
votes
2answers
866 views

Solitaire Chess- Round 2

This is another Solitaire Chess puzzle like this earlier puzzle. Rules: Pieces move as in regular chess Every move must be a capture When there is only 1 piece left, you win.
15
votes
9answers
3k views

Red and Blue in the Chocolate Fountain Room

Where: Hackanoogie Prison. When: Who cares? The Master Key Keeper had had a really good day and in a fit of insanity and niceness decided to let all the inmates to go free if they manage to carry ...
10
votes
1answer
834 views

Is a fake coin lighter or heavier? [closed]

There are 16 coins, 3 of which are slightly heavier or lighter than the others. The counterfeit coins have the same weight but it is not known whether they are heavier or lighter than the genuine ones....
16
votes
2answers
1k views

Empty one pile of balls and win

There are two piles of balls. One contains 5 balls and the other contains 18 balls. A and B are playing the following game: In each round, a player has to move balls from the larger pile to the ...
1
vote
1answer
139 views

Outsmarting a Con (sales) man

During a fun filled golf event vendors have set up stalls offering different things to participants like golf gear, food, clothing etc. Participants can also win gifts in putting contests, drives and ...
0
votes
0answers
111 views

Helping a team guess a correct number without prior knowledge [duplicate]

I am new here and would like to request your explanation for a riddle I saw. It is quite interesting but I don't understand it and would like your assistance to understand what's going on, how to &...
10
votes
3answers
557 views

Optimal refueling strategy

On the way home from work, I want to refuel my car. There are 5 petrol stations along the way that all have a different price for petrol. I know that the prices will be in the range [A, B], chosen ...
6
votes
2answers
273 views

Holiday Madness: Draw a line through all the gifts

Can you collect all the gifts? The rules: Start from the star At each intersection are arrows. You can only move through the intersection in accordance with the direction of the arrow. (e.g If you ...
1
vote
1answer
144 views

Variation of 100 prisoners [duplicate]

There are 100 prisoners, each prisoner is given a number between 1 and 100 without knowing which number, the number can repeat and not all of the numbers must be given. Each prisoner in his turn can ...
5
votes
3answers
290 views

Optimal Strategy for Matching Pairs

I found a reality TV show recently that I thought would make a fun puzzle. On the show are 10 men and 10 women that have been "matched by experts" (ie. randomly paired). Their goal is to ...
2
votes
1answer
141 views

Looking for a strategy for assembling a Minesweeper grid knowing only the tiles but not their positions

This puzzle consists of 36 tiles. Each tile has a digit and may or may not have a mine. The goal is to assemble a 6×6 Minesweeper grid — in other words, each digit must equal the number of mines ...
8
votes
2answers
513 views

Strategy for solving a 3D maze

Given enough time, you can solve a large 2D maze by simply following a wall. Is there any similar strategy for solving a 3D maze that can be used (no marking/memorizing places you've seen in the maze ...
13
votes
1answer
15k views

How do I approach a “stuck” game of minesweeper?

I've played many a-game of minesweeper, and I frequently reach positions in which there is no logical, deterministic way to come to a conclusion about how I should solve the puzzle. How should I ...
7
votes
2answers
288 views

Another coin weighing puzzle, now including shifty coins!

You are, as you have been many times before, in some place that has a balance scale and 12 coins. 11 are all "normal" and stay normal, but one of these coins, however, is shifty -- as soon ...
1
vote
0answers
132 views

Social Distancing Colors - A New Type of Puzzle? [closed]

I think I just thought of a new type of puzzle: Social Distancing Colors. Each of the colors in the rainbow represents at least how much one has to distance by: Red is 6m, Orange is 5m, Yellow is 4m, ...
35
votes
12answers
9k views

The total cost of salaries in a company

Story Version (scroll for TL;DR) It's the end of the first quarter of 2017. This means it's the end of the 2016 fiscal year (at least in my country it is). It's time to draw the line. So the CEO did ...
15
votes
8answers
3k views

How could Larry get his friends on a plane without knowing their weights? [duplicate]

This riddle was inspired when I watched the latest (as of this post) episode of Curb Your Enthusiasm (S10E4), in which Larry is faced with a dilemma that he never really solved. The dilemma is as ...
10
votes
2answers
882 views

Save the person in 14 moves on a cross

A person was trapped in a building, and you have to save him. You are a police officer and you will arrive at the building at 7 o'clock in the morning. The building looks like this: Every 2 minutes, ...
-3
votes
3answers
226 views

10 Rats and 10 bottles, find one non poisonous bottle with least rats killed [closed]

There are 10 bottles of liquid, out of which 9 bottles are poisonous and one bottle of liquid is non-poisonous. The rats are to be fed this liquid one bottle at a time and rats die instantaneously. ...

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