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[fit] Permutations

##The distinct ways that a group of items can be arranged.

#Example: [1,2,3]

[
  [ 1, 2, 3 ],
  [ 1, 3, 2 ],
  [ 2, 1, 3 ],
  [ 2, 3, 1 ],
  [ 3, 1, 2 ],
  [ 3, 2, 1 ]
]

How many permutations?

^It turns out that we can mathematically determine the number of permutations for a given set of values. If we can only use each value one time (but must use it 1 time), then the solution is n!.

What kind of problems will you see?

Given two strings, determine if they are permutations of one another.

Is "stop" an anagram of "tops"?

^ Yes, this is the same as the previous question. It's just asked in a different way.

How many ways can we...?

^Example- There are 4 restaurants that I want to visit that are across the city from one another. How many different ways (order) can I visit the restaurants? A shelter has 4 dogs. How many different ways can the dogs be adopted among 4 people who are interested in adopting?

Write an algorithm to determine all possible permutations of a given string.

Traveling Salesman Problem

The Traveling Salesman Problem (often called TSP) is a classic algorithmic problem in the field of computer science. It is focused on optimization. In this context better solution often means a solution that is cheaper. TSP is a mathematical problem. --Wikipedia

^ This is a big problem, but when broken down into parts, one of the parts is essentially a permutation problem.

#[fit] Permutation Algorithms to Consider