Questions tagged [river-crossing]
For questions regarding how to get items or people across something obeying a set of rules.
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Wounded Soldiers/Crossing a Bridge Puzzle - checking a solution
I am working on a Prolog university assignment, where we have to determine what the shortest time is for 4 wounded soldiers to cross a bridge to safety. This seems to be a variation of the more common ...
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votes
2
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Triple up, pair off, and single out
Can you transform this word triple
PELTS SORES DIVAN
into this word triple
PLOTS DIVES SANER
just by swapping pairs of ...
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2
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An overcomplicated Boat Puzzle
Based on Xkcd's Boat Puzzle
At the riverbank, a succession of people have given you a large lump of objects to transport across the river. These are:
101 cabbages
2 goats, one of which eats wolves
4 ...
- 1,175
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3
answers
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A small pond-crossing
While walking through the flower gardens, you encounter a small group of fairies stuck on a lilypad. There are 2 red fairies, 2 yellow fairies, and 2 green fairies, and they have nothing besides a ...
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1
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A frugal canal-crossing
You've been sent out to round up some escaped animals. While you have some of them under control now, you've ended up trapped on the wrong side of a canal. Currently, you have 5 animals:
A perivine, ...
- 1,175
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Escape across the floorboards
A mad lexophile sits alone in his apartment obsessively rearranging his Scrabble tiles and writing words on every available surface, even filling each floorboard with a word. The Scrabble tiles have ...
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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 ...
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A river crossing puzzle
Here is a puzzle I came up with.
Ali and Billie are approaching a river from one side, and Casey and Devin from the other side.
Ali shouts: "Do you two also want to cross?"
Casey shouts back:...
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Minimum time to cross the bridge
There are 6 friends A, B, C, D, E and F who want to cross a bridge. However, there are two problems. First, the bridge can only accommodate two persons at a time. Second, it is night and they need the ...
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1
answer
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Strait-Crossing Puzzle
You are on an island, and must transport 3 moose across a strait to the mainland. While they can swim across the strait, they will likely end up running into the forest and leaving you behind. While ...
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3
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How do I find the least number of times a shuttle can travel from one place to another?
I often see this situation in exams and I'd like to know if there is any kind of algorithm or shortcut that I can use to solve this puzzle instead of just guessing.
The problem is as follows:
A space ...
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Terrorists transporting Hostages through the desert
You belong to an intelligence agency that is monitoring some terrorists. There are three of them in the Hideout A with three hostages and a bomb. Unfortunately, this hideout is extremely secure. But ...
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1
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Family river-crossing
A family of six is crossing a river with a 2-passenger boat. The family includes the following members: Dad, Mom, Maid, Boy, Girl & Dog. Only the 3 adults can row the boat and the dog counts as a ...
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Missing lattes and mutually mistrustful words
It's always amusing to watch two kids who don't trust each other swap baseball cards by exchanging them at exactly the same moment. Words can be equally mistrustful about trading their letters. ...
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Boat children and army crossing the river puzzle
During the war, a small detachment found itself
confronted by a deep and wide river. However, they found a small boat in which
two-children were rowing about. It was a very small boat and can only ...
- 1,056
11
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1
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Don't look back, crazy clown
Start with these two words
INSANE RETROSPECT
and see if you can get them to exchange places by transferring one letter at a time. With each ...
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votes
1
answer
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Uncover Lenny Fingers' street hustle
Lenny Fingers is out on the street again, hustling people with his shell games. This time, he's using words.
As you walk by, Lenny grabs you with an enthusiastic smile and shows you two words side-...
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The cat exchanges places with a drawing of the cat
Given
CAT RENDERING
see if you can get them to exchange places, resulting in
RENDERING CAT
by ...
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1
answer
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Farmer needs to get his word across the river
In the spirit of the classic river-crossing puzzles:
...
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3
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1
answer
481
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Rigorous way to solve the river crossing problem
I encountered this classic brain teaser:
Four people, A, B, C and D need to get across a river. The only way to
cross the river is by an old bridge, which holds at most 2 people at a
time. ...
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Another river with some extra letters
2 men are at a river. There is a boat. It holds only one person at a time.
They both cross the river and continue their way...
How?
P.S. No Uber, helicopters, bridges, ropes, or anything else close ...
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numbers want to cross a river, but their sum must be a square number
In the world of numbers, numbers 1 to 9 want to cross a river,
They have a boat which can take 1 to 3 numbers,
But sum of the numbers must be a square number.
The boat can not sail back itself, so ...
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7
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Ali Baba and the 10 thieves
EDIT: This puzzle originates from the "International Mathematics Tournament of the Towns", and was published in the book "S.M.A.R.T circle overview" by Professor Andy Liu. The author has (albeit a ...
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3 cannibals and 3 missionaries on different side of the river
Three missionaries on the left side of a river and three cannibals on the right side of the river want to cross a river using a boat which can carry at most two people, The boat is on the cannibals ...
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When do missionaries and cannibals problems have solutions?
In the Missionaries and Cannibals problem:
Three missionaries and three cannibals must cross a river using a boat
which can carry at most two people, under the constraint that, for
both banks, ...
- 41
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votes
3
answers
1k
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Zombie horde incoming! [duplicate]
Here is a puzzle I found on youtube's Ted-ed channel and found quite fun to solve.
You and 3 more people are for some reason running away from a horde of zombies in the darkness while holding a ...
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votes
2
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Cross the river with a small (4 spaces) boat
Giant, Slimy, Boy, Romy and Fatty want to cross a river.
To cross the river there is a small boat.
The boat only has 4 spaces. Every one can row the boat.
At the boat, Giant needs 4 spaces.
Slimy ...
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5
answers
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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.
...
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Quick!!! You got only 30 seconds
There are two checkpoints on a road namely Pt. A and Pt. B. There are 5 persons standing at the Pt. A namely P , Q , R , S, T. They have a car such that P , Q , R , S , T can travel to Pt. B in 1 , 3 ,...
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answer
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Ancient mysteries of the Arab world [duplicate]
If we want to convey the lion and the sheep and feed from the bank of the river to the other how to do it?
and the lion will not eat the sheep and the sheep will not eat the feed
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Bridge's riddle [duplicate]
You're in a group of people going for an internship in a remote mountain lab. By mistake you pulled a lever with a skull just out of curiosity and it released some zombies. So you and your group had ...
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2
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Crossing The River (Humans And Monsters Puzzle With A Twist)
3 couples on one side of a river. Aa Bb Cc (caps representing husbands, lowercase representing wives)
One boat in which 2 people can travel at a time.
At least one person must row the boat wherever ...
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2
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Numbers nonexistent
This problem is one of the hardest problems I have ever encountered.
If you don't trust links, here it is:
There are some Couples wanting to cross a river by a boat. The boat can carry at most 3 ...
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1
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A man, a chicken, and a fox? [duplicate]
A man lives in a small house with a farm as his back garden and has a river beside his house. On the other side of the river is a shop. One day, he visited the shop, he bought a chicken and a fox for ...
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4
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Can you solve this Bruce Wayne logic puzzle?
This variation of the classical Farmer Goat puzzle was in a puzzle contest at my college two years ago.
Here it goes.
Mr. Bruce Wayne is very fond of parties. Well, he’s more fond of girls, but, ...
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5
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How can the animals get across the river without a fight breaking out?
There are three dogs and three cats that have to be transported across a river: a big dog, a medium dog and a small dog, a big cat, a medium cat, and a small cat.
Rules:
The raft can carry two ...
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2
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The case of the 4 campers and the rickety bridge! [duplicate]
Four people need to cross a rickety rope bridge to get back to their camp at night. Unfortunately, they only have one flashlight and it only has enough battery left for seventeen minutes. The bridge ...
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3
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$n$ couples crossing a river
There are $n$ couples on one side of the river. Nobody is on the other side. They have a boat that accommodates up to 2 people. For every trip across, someone(s) must bring the boat back as well. The ...
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3
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$n$ monsters and $n$ people
There are $n$ monsters (M) and $n$ people (P) on the left side of a river. Nobody is on the right.
They have a boat that can hold up to 2 beings. At no point on time may either of these be true:
$$M_{...
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1
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How can the man get across the river with the two animals and the cabbage? [duplicate]
A man has a wolf, a goat, and a cabbage. He must cross a river with the two animals and the cabbage. There is a small rowing boat, in which he can take only one thing with him at a time. If, however, ...
user5049
-1
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1
answer
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A Fox, a Chicken, a Pile of Seeds, and a Boat [duplicate]
There's 2 islands, 1 island has a pile of seeds, a chicken, and a fox. There's also a boat next to this island, you have to get it all across with minimum uses of the boat. You can only take one ...
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Fastest way to cross a river: four people with different rowing speeds
This problem is commonly cited as a Microsoft interview problem, although I have paraphrased it here to involve a river and a boat instead of a bridge and a flashlight, and tweaked the crossing times ...
user88
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4
answers
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Strategy to solve the Missionaries and Cannibals problem
In the Missionaries and Cannibals problem:
Three missionaries and three cannibals must cross a river using a boat which can carry at most two people, under the constraint that, for both banks and ...
- 1,249
10
votes
2
answers
752
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What is the maximum number of items in a river crossing puzzle?
A River Crossing puzzle puts limits on the number of items that may cross a boundary, with limits on what may be left together. The "Fox, goose and bag of beans" is one of the earliest examples. Of ...
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Learning to Solve a River Crossing Puzzle
I have seen many variations of the following puzzle:
Once upon a time, a farmer went to the market and purchased a fox, a goose, and a bag of beans. On his way home, the farmer came to the bank of ...
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