99 Problems

Solutions to 99 Problems implemented in Reason.

Status

Currently in progress.

Working with lists

No.	Description	Solution		No.	Description	Solution
01	Last element	completed		15	Replicate	completed
02	Last two elements	completed		16	Drop every N'th	completed
03	K'th element	completed		17	Split	completed
04	Length	completed		18	Slice	completed
05	Reverse	completed		19	Rotate	completed
06	Palindrome	completed		20	Remove	completed
07	Flatten	completed		21	Insert	completed
08	Eliminate duplicates	completed		22	Range	completed
09	Pack duplicates	completed		23	Random select	completed
10	Run-length	completed		24	Random numbers	completed
11	Modified run-length	completed		25	Random permutation	completed
12	Decode run-length	completed		26	Combinations	completed
13	Direct run-length	completed		27	Group	completed
14	Duplicate	completed		28	Sort by length	completed

Arithmetic

No.	Description	Solution		No.	Description	Solution
31	Prime	completed		37	Improve 32	completed
32	GCD	completed		38	Compare 32 and 35	completed
33	Coprime	completed		39	List prime numbers	completed
34	Euler's totient	completed		40	Goldbach's conjecture	completed
35	Prime factors	completed		41	Goldbach compositions	completed
36	Prime factors (pair)	completed

Logic and Codes

No.	Description	Solution
46	Truth tables for logical expressions	completed
47	Truth tables for logical expressions (2)	completed (combined with 46)
48	Truth tables for logical expressions (3)	completed
49	Gray code	completed
50	Huffman code	completed

Binary Trees

No.	Description	Solution		No.	Description	Solution
54A	Check Binary Tree	No need as type checked		62	Collect internals	completed
55	Completely balanced	completed		62B	Collect nodes at a level	completed
56	Symmetric	completed		63	Complete binary tree	completed
57	Binary search trees	completed		64	Layout 1	completed
58	Generate-and-test	completed		65	Layout 2	completed
59	Height-balanced	completed		66	Layout 3	completed
60	48 with N nodes	completed		67A	Stringify	completed
61	Count leaves	completed		68	Preorder and inorder	completed
61A	Collect leaves	completed		69	Dotstring	completed

Multiway Trees

No.	Description	Solution
70B	Check Multiway Tree	No need as type checked
70C	Count nodes	completed
70	Node string	completed
71	Internal path length	completed
72	Bottom-up order	completed
73	Lisp-like tree	completed

Graphs

No.	Description	Solution		No.	Description	Solution
80	Conversions	completed		85	Graph isomorphism	completed
81	Path	completed		86	Graph coloration	completed
82	Cycle	completed		87	Depth-first traversal	completed
83	Spanning trees	completed		88	Connected components	completed
84	Minimal spanning tree	completed		89	Bipartite graphs	Not implemented

Miscellaneous Problems

No.	Description	Solution		No.	Description	Solution
90	Eight queens problem	completed		95	English number words	completed
91	Knight's tour	completed		96	Syntax checker	completed
92	Von Koch's conjecture	completed		97	Sudoku	completed
93	An arithmetic puzzle	completed		98	Nonograms	completed
94	K-regular simple graphs	completed		99	Crossword puzzle	Not implemented

Acknowledgement

References

• 99 Problems in OCaml

Insipration

• 99 Problems in Haskell
• 99 Problems in Lisp
• 99 Problems in Prolog