algorithm playground
- leetcode
- several coding tests
- etc..
- start from swift 5
- patterns
- linear queue
- circular queue
- linked list
- factorial
- binomial coefficient
- fibonacci
- how many case to pay
- integer partition
- n-bit gray code
- path finder
- find prime number
- find subset
- thief's knapsack
- find comboset
- check alphametic
- self descriptive