Questions tagged [strategy]

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

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2
votes
3answers
296 views

How many pilots do they need?

I have just watched this old riddle video from Ted-Ed. It basically asks how can three pilots coordinate their flights such that the professor (one of the three pilots) can circumnavigate the earth. I ...
9
votes
1answer
254 views

Survive the infinite zombie attack II

Zombies are back again. Same as last time, You're at the origin, and zombies occupy the points $(100𝑖,100𝑗)$ for all integers $𝑖,𝑗$ except the origin, as shown below: The ratio of your speed to ...
5
votes
2answers
271 views

Even and odd game variant

You are playing a game with your friend on a $7$x$7$ grid board. In every turn, you begin by putting a $0$ (zero) on any empty square on the board, and then your friend puts a $1$ (one) on a different ...
3
votes
1answer
223 views

100 Prisoners and 3-state clock

100 Prisoners and a clock seems far too easy on the prisoners, so the exact same question, except that they must change the clock by exactly 4 hours: There are 100 prisoners who are given a chance at ...
1
vote
1answer
142 views

Adding up divisors of integers

Alice and Bob play a game, taking turns. Alice starts and writes an integer between 1 to 10 on a blackboard. Then Bob adds any integer between 1 to 10 to this number and writes it on the blackboard. ...
1
vote
1answer
231 views

1 lion, with a zebra and a fixed enclosure

Background See the puzzle Variant of lion and 100 zebras from @ghosts-in-the-code which remains unsolved years after it was posted. Several times in the last couple of years I've started to write up ...
22
votes
5answers
2k views

retsubkcolB Spelled Backwards

How would you enter retsubkcolB spelled backwards into the comment box below and press the "Add comment" button (nothing will happen, as there's only 11 letters) using at most 10 clicks in ...
-4
votes
6answers
679 views

Variation of 100 coins puzzle (no flipping) [closed]

You have 100 coins laying flat on a table, each with a head side and a tail side. 10 of them are heads up, 90 are tails up. You can't feel, see or in any other way find out which side is up. You ...
5
votes
1answer
230 views

How did the king pay the worker? [duplicate]

A humorous king pays his worker with one inch gold bar everyday. He had a $31$ inches gold bar and he paid the worker $31$ days of a month cutting it in just $4$ places. How is this possible? Taken ...
21
votes
7answers
2k views

What is the minimum number of helpers that an explorer need to cross the desert?

There is a desert which can be crossed only by walking and this takes six days. The explorers of the desert can carry at most four days' water and food. If they want, they can take helpers with them. ...
7
votes
4answers
913 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
232 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
170 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 ...
21
votes
2answers
3k 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 ...
2
votes
1answer
71 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 ...
7
votes
3answers
423 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 ...
3
votes
0answers
195 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
297 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 ...
5
votes
1answer
456 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,...
6
votes
2answers
239 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), ...
12
votes
3answers
744 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
299 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 ...
16
votes
7answers
2k views

Flashlight and 8 batteries

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 them are charged while the ...
7
votes
4answers
773 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....
9
votes
1answer
364 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
202 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 ...
5
votes
1answer
231 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
926 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
331 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 ...
-4
votes
1answer
108 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
vote
0answers
77 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'...
10
votes
1answer
850 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....
1
vote
1answer
146 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
112 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
1answer
147 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 ...
6
votes
2answers
275 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 ...
2
votes
1answer
143 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
518 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 ...
5
votes
3answers
295 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 ...
1
vote
0answers
133 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, ...
7
votes
2answers
291 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 ...
-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. ...
10
votes
2answers
883 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, ...
10
votes
3answers
561 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 ...
2
votes
2answers
141 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 ...
3
votes
1answer
186 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 ...
0
votes
0answers
95 views

Mastermind Swaszek Strategy [duplicate]

I'm writing a paper for school at the moment (12 grade) and I came across the name Swaszek. His strategy is often referred to as being solvable without any computers. I have read a couple of articles ...
2
votes
1answer
129 views

Crossing a river with bonds and beefs

Here is a river crossing puzzle (note that whenever I use the term "colors", I mean the squares): Yellow and Red are on one side of the river, while Pink, Blue, Green and Black are on the ...
0
votes
1answer
160 views

Fill grid with Bs

Here is a letter grid: Here are the rules as to how to manipulate the letters in the grid: A marker starts at the first square. For each move you can move the marker one square either up, down, left ...
1
vote
1answer
124 views

Minimum moves to lose grid game

Here is a number grid: And here is the rule for how to move: A move consists of selecting two adjacent squares (either vertically, horizontally or diagonally) and dividing the sum of the two numbers ...

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