Questions tagged [strategy]

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

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2
votes
1answer
380 views

Numberlink strategy

Note: This is not asking for a general strategy, you can find that here. Is the following a valid strategy in solving Numberlink (Flow Free) puzzles (I like to call it 'unwrapping the grid'): ...
7
votes
3answers
804 views

Dinosaur Egg Drop v2

This question is a little different and kinda follow-up version of Dinosaur Egg Drop 1- You have 100 story building and 6 Apatosaurus dinosaur eggs. 2- You have 81 story building and 3 ...
11
votes
1answer
625 views

A Tic-Tac-Toe variant with three marks - winning strategy and chances

We start with a usual $3 \times 3$ grid, $3$ different marks (say, $X, O, I$) and $2$ players. Player $A$ has to make a vertical, horizontal or diagonal line made of $3$ identical marks (XXX, OOO or ...
3
votes
3answers
581 views

A variation of the poisoned bottle problem

Old story. The King has received X=950 bottles of wine, exactly one of which is poisoned enough to kill a man exactly 24 hours after ingestion. The King wants to feed some N prisoners some mix of the ...
5
votes
2answers
588 views

Lead the murderers out

Imagine you are in a big hall. Except you, there are 20 other people. In the beginning, you have different pieces of paper: ...
26
votes
3answers
2k views

Finding digits that sum to 15

Rand and Rubio are playing a game in which they each take turns to pick a digit between 1 and 9, without replacement (i.e. all digits chosen are distinct). If one of them manages to get three digits ...
10
votes
4answers
1k views

JonMark Perry's Grid Logic Puzzle

Consider the following puzzle type proposed by JonMark Perry. Start with a square grid of arrows, each one pointing in one of the four cardinal directions. For example: You start at the ...
7
votes
1answer
778 views

Tic Tac Toe Recursive

Related: Connect 4 Recursive We have a mega tic tac toe grid. Each of the nine cells of the mega grid has a smaller tic tac toe grid. In total we have 81 cells that can be filled. (Maybe imagine a ...
10
votes
6answers
9k 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 ...
6
votes
2answers
6k views

Strategy for solving Flow Free puzzles

There is an app on the app store called Flow Free. Basically, there is a grid with a few sets of colored dots, and you need to connect each dot to the other dot of the same color, filling up the ...
18
votes
8answers
2k views

30 fake coins out of 99 coins

You are given 99 coins which consists of 30 fake ones. You also have a digital balance scale with perfect precision that shows how much difference between weighs you put on. For example, if you put 10 ...
7
votes
1answer
496 views

Connect 4 Recursive

Here is a variant of the standard connect 4. There are seven connect 4 grids (size 6 by 7) numbered 1 to 7. Each grid has the columns numbered 1 to 7. The person who starts selects any one of the ...
6
votes
2answers
508 views

Hopping Frogs puzzle variant

There is an old puzzle which has various names such as Toads and Frogs, Jumping Frogs, Hopping Frogs, Leap Frog, etc., and which has been asked here before. I'd like to share a variant of this puzzle ...
12
votes
1answer
2k views

What is the strategy to solve Simon Tatham's Twiddle?

Consider the goal 3x3 position: You must reach this position by rotating 2x2 blocks by some multiple of 90 degrees like so: Orientation of each individual number is preserved. What is the ...
15
votes
3answers
1k views

6 Water Glasses Upside Down

There are 6 water glasses as shown in the picture below: You need to turn all of them upside down with the rules below: You have to choose any 5 of them at every turn. Chosen ones need to be turned ...
11
votes
3answers
829 views

16 Two Colored Line up v2

This is the follow-up question for 16 Two Colored Line Up This time, you are not supposed to solve it, but find the worst possible arrangement for each square, which will make the number of steps ...
8
votes
2answers
361 views

16 Two Colored Line up

We have a different type of puzzle which consists of 4x4 board with numbers on it; Your task is to put numbers in the correct order as given in the diagram above. In each step, you can take one ...
31
votes
6answers
5k views

Will a greedy algorithm solve Tatham's Flood?

I was just investigating some of the puzzles on Simon Tatham's website, and came across Flood, in which we start with an $n\times n$ grid of cells each of which is filled with one of $k$ predetermined ...
2
votes
5answers
476 views

Coin Splitting Game [closed]

There are 8 coins to be divided between A and B. A first makes an offer of how to divide the 8 coins between them. If B refuses A’s offer, then now it is B’s turn to make the offer, but this time 4 ...
9
votes
4answers
1k views

The Universe and Spaceships

It is given that there are infinite planets in the universe and every planet has exactly one spaceship on it. (Thus there are infinite spaceships too.) The distance between planets is unknown. As ...
2
votes
2answers
723 views

Which switch is faulty?

How to solve this puzzle? This puzzle is taken from the book The Ultimate IQ Test Book by Philip Carter and Ken Russell.
6
votes
5answers
6k views

River Crossing Puzzle

There is a family which contains 4 members: Dad, Mom, Son, Daughter. They have a boat which carries only 100 kg at a time. Mom and Dad weigh 100 kg each, while Son and Daughter weigh 50 kg each. ...
8
votes
3answers
2k views

Reverse the order of 8 poisonous substances

8 very poisonous substances named s1 to s8 are kept in a safety room. The substances are kept in ascending order (s1,s2,s3,s4,s5,s6,s7 and s8). In the room there are 3 robots. First robot can "rotate ...
16
votes
10answers
3k views

5 people each have 5 equal cards

A competent logician is playing cards with four of his friends, so that there are a total of 5 people sat around the table. Each player has the same 5 cards, showing A, 2, 3, 4, and 5 (Ace being low). ...
-1
votes
3answers
143 views

Find your market [closed]

There are 100 people from different nationality, gender, profession etc in a ballroom are taken as captives by an underground gang. Each of captives are given 5 dollar bills. And said After 30 ...
7
votes
3answers
375 views

A game of Connect 4++

This is an entry to the 17th fortnightly topic challenge. Alice and Bob are playing connect four. Bob is tired of losing all the time, so he suggests changing the rules. He wants to drop 2 pieces ...
4
votes
4answers
318 views

Limited functions calculator

There's a calculator with 10 functions exp, square, sin, cos, tan and their inverses. We need to convert 0 to 1 to 2 to 3 to -3. Note: Addition, subtraction, multiplication and division are not there
5
votes
5answers
508 views

Identify who is who between 3 persons who tell the truth and lie alternately

Dipsy tells the truth in 1 day and lies in the next day alternately. If today he tell the truth, tomorrow he will lying, 2 days later he will tell the truth, and so on. Lala tells the truth in 2 ...
9
votes
4answers
548 views

4 function calculator puzzle

You have a basic but very problematic four function calculator. That is, the keys are 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, +, -, x, /, and =. However, all the keys are scrambled up in an unknown order, and ...
31
votes
10answers
6k views

100 Prisoners and a clock

There are 100 Prisoners who are given a chance at freedom. The prisoners are randomly picked to visit a room where there is only a nonfunctional wall clock with a ...
-1
votes
1answer
101 views

What Land Grant Would You Select? [closed]

A king has just decided to divide up very large parcel of land and provide land grants to subjects that want to start a farming operation. This particular king and his advisors were into circular ...
10
votes
6answers
4k views

Guess a number between 1 to 27 with 3 Yes/No/Maybe questions [duplicate]

Your best friend (Bob) comes to you with this problem. The Problem His teacher (Mr. Sam) will ask Bob to work out a number in his head between 1 and 27. Bob has to find the correct number, by asking ...
2
votes
2answers
151 views

Halve or diminish, and race to unity! v2

This is follow-up question to Halve or diminish, and race to unity!. Alice and Bob are playing a game. In the beginning, they randomly choose a positive integer between $2$ to $n$ where $n$ is a ...
6
votes
5answers
274 views

Halve or diminish, and race to unity!

Alice and Bob are playing a game. In the beginning, the integer $9172016$ is written on a blackboard. In a move, a player, can: either decrease the number on the board by $1$ (i.e., replace $n$ by $n-...
4
votes
2answers
430 views

The Lazy worker and the Punctual Boss

Before we start, idea blatantly stolen from this puzzle Tom has found another job, with another Boss who always arrives at the same time on weekdays. This boss, however, has a different policy. If ...
4
votes
6answers
798 views

Best strategy to get all heads/tails from three coins

Your friend has 3 fair coins: a dime, a nickel, and a quarter. She places them on a table behind you. She can arrange then in any pattern of heads and tails as long as they are not all the same. You ...
27
votes
3answers
4k views

16 pawns on a chess board with no three collinear: how do I go about solving this?

Here's a problem that was posed to me but I haven't seen anything about it anywhere online! I'm beginning to wonder if I'm just getting played! You have a chessboard and sixteen pawns. The puzzle is ...
8
votes
7answers
1k views

7 Numbered Balls Game

You are walking on the street and notice a guy gambling with some other guys and you start to watch. The game principle is pretty easy. There are 7 balls in a pouch and you have 3 balls to draw ...
8
votes
2answers
715 views

Lots of Gold Golden Coins and a Scale

Following my previous question: Lots of Gold Stacks and a Balance Scale You are given 10 stacks, each stack consisting of N golden 10g-coins and a digital scale with perfect precision that shows ...
-1
votes
2answers
156 views

Speeding up half way [duplicate]

On my way to the supermarket, I walk at a certain speed. I want my average speed for the back and forth trip to be twice that speed. At what speed should I go back home to reach that goal?
4
votes
3answers
540 views

Dr. G's Interesting Theorem on Playing Cards

Dr. G has spent his last weekend with analyzing $n$ number of cards which are numbered from $1$ to $n$. He has a fair shuffling machine for his cards and while playing and drawing some cards, he uses ...
39
votes
1answer
2k views

Polynomial game with Devil

You die, and awake in Hell. Satan awaits you, and has prepared a curious game. On a blackboard, he has written the polynomial $x^2+x+666$. He explains the rule: On each day at $12$ noon, you must ...
19
votes
4answers
2k views

Obtain the “Master of stones” title

Note : the mechanisms described in this puzzle are related to those found in this question. This is a game of 2 players. Each player can pick up 1, 2, or 3 coins in any pile (copper , silver , gold) ...
12
votes
3answers
784 views

Can the policeman actually catch the thief, instead of shooting?

The ACLU won a lawsuit against the Squareshire Police Department, alleging that his policy of shooting suspected thieves on sight was unconstitutionally excessive force. The argument that carried the ...
67
votes
5answers
7k views

Can the Policeman catch the Thief?

The town of Squareshire has six streets: four sides of a square and the lines joining the midpoints of opposite sides. $\hskip2in$ A policeman is chasing a thief along these streets. If they are ...
14
votes
1answer
496 views

Money Game with $1025$ cards

Alice is playing a game with Bob. They have $1025$ cards, with the numbers $0,1,2,\cdots , 1024$ written on them. Each card contains exactly one number and each number is written on exactly one card. ...
21
votes
4answers
2k views

Even and Odd game

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 ...
3
votes
3answers
515 views

Get together to-get-her ;)

You are going to meet your school friends after four years. You are very excited about it. You have planned to gift everyone a chocolate. On the day of get-together you meet everyone and feel happy ...
21
votes
5answers
1k views

Detectives vs Nelson: The Chessboard Serial Killer

This is about Nelson, a serial killer who, after each murder, leaves a chess diagram in the scene of the crime. These chessboards give the detectives the opportunity to decipher where, how and when ...
3
votes
2answers
335 views

Perfect strategy for the 2nd player in 'The coins on a table game'

I've just seen this and looked at the duplicate post it directs me to. I'm interested in a point raised in one of the comments in the answer, although it wasn't resolved in that question. It is ...