Questions tagged [strategy]

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

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100 prisoners and a secret number

There are 100 prisoners numbered from 1 to 100. They know their own numbers. There is an interrogation room with a table and an envelope. The envelope contains a secret number - an integer chosen ...
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479 views

A three-way bet

Alice, Bob and Carole are playing a betting game. At the beginning, they have 20 chips in the common pot. They move alternatively in the order of Alice, Bob and Carole. In their move, a player ...
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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 ...
• 123
556 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 ...
281 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 ...
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352 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 ...
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2k 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,...
578 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), ...
865 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 ...
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359 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 ...
• 69
3k views

Flashlight and 8 batteries

Source: this TED-Ed video. A flashlight requires 2 AA-type batteries to operate. Both these batteries need to be charged for the flashlight to provide light. We happen to have 8 batteries, but 4 of ...
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844 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....
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393 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 ...
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236 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 ...
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259 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 ...
966 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’...
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1 vote
346 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 ...
128 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 ...
• 1,505
1 vote
82 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'...
• 11
1k 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....
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1 vote
198 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 ...
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125 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 &...
1 vote
219 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 ...
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305 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 ...
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200 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 ...
• 171
883 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 ...
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422 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 ...
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1 vote
152 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, ...
317 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 ...
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243 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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925 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, ...
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628 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 ...
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163 views

Save the poor Gingerbreadmen!

The poor gingerbread men want to survive to Xmas (they don't mind being eaten afterwards). If at least one of them doesn't guess his hat correctly, they will all be cruelly eaten before Xmas. This is ...
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233 views

Variation of 100 Prisoners' names in boxes

100 Prisoners' Names in Boxes The following puzzle is a variation of the above puzzle. Names in Boxes The names of 4 prisoners are placed in 4 wooden boxes , one name to a box, and the boxes are ...
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