## Iteration
* print a linked list in reverse order
factorial
any loop based problem

## Breaking into sub problems
* towers of Hanoi
* fibonacci

## Selection
* knapsack problem
* word break
* phone spell
* N Queens

## Ordering (permutations)
* find all permutatioons of inputs
* find all n digit numbers whose digits sum to a specific value
* word squares

## Divide and Conquer
* searching a sorting in trees
* merge sort
* generate all BSTs for a set of terms
* find all valid parentheses

## Depth First Seach
* search in a tree
* probability of a knight on a chessboard