# Sudoku Funpark Creating worlds most inefficient Sudoku solver, by trying every option, without any smart approach. _(This was a learning project to get a better grasp of Golang. But more important; It was fun to do!.)_ ## Goals * Create the most inefficient Sudoku solver imaginable * Be a learning experience for the Go programming language I wrote [a blog post](https://blog.ligthert.net/posts/exploration-fun-and-process-cycles-of-sudoku/) about this. ## Features * Worlds least efficient Sudoku solver * Ability to assign a number of CPU cores to this task * Split workloads among several computers ## Usage To use the sudoku solver, run the binary with all the `-row` parameters available. Use other parameters to tune our output or CPU usage. ``` Usage of ./sudoku-funpark: -numcpu int Number of CPU cores to assign to this task. (default 12) -output string Type of output. 'human' for human readable. 'flat' for flat as stored in memory output. 'json' for JSON output. (default "human") -part int Process part x in n parts. Cannot be lower than 1, or higher than specified in split. (default 1) -print string 'short': normal output;'long': normal output with timestamps; 'silent': Only print the results; (default "short") -row1 string 1st row of the sudoku puzzle. (default "000000000") -row2 string 2nd row of the sudoku puzzle. (default "000000000") -row3 string 4rd row of the sudoku puzzle. (default "000000000") -row4 string 4th row of the sudoku puzzle. (default "000000000") -row5 string 5th row of the sudoku puzzle. (default "000000000") -row6 string 6th row of the sudoku puzzle. (default "000000000") -row7 string 7th row of the sudoku puzzle. (default "000000000") -row8 string 8th row of the sudoku puzzle. (default "000000000") -row9 string 9th row of the sudoku puzzle. (default "000000000") -split int Split the tasks in n parts. This depends on the availability of the first row. (default 1) ``` Instead of using the 3x3 blocks with 3x3 digits, it uses horizontal rows from top to bottom. ## Example To see the solver in action, run the tool with the following parameters. For a short running (~14 seconds) example: > $ ./sudoku-funpark -row1 769104802 -row2 154800060 -row3 832700154 -row4 600900328 -row5 045328670 -row6 328670945 -row7 597410280 -row8 006283090 -row9 200590006 For a long running (~1 hours 15 minutes) example: > $ ./sudoku-funpark -row1 769104802 -row2 154800060 -row3 002700150 -row4 600900308 -row5 045328670 -row6 328670945 -row7 597410280 -row8 006283090 -row9 200590006 The outpot (of the short running parameters) will look something like this: ``` ./sudoku-funpark -row1 769104802 -row2 154800060 -row3 832700154 -row4 600900328 -row5 045328670 -row6 328670945 -row7 597410280 -row8 006283090 -row9 200590006 Loading blocks... Done! (38.957376ms) Populating blocks... Done! (92.087174ms) Number of (potential) solutions: 26542080 Validating solutions Processing: 8% (2131893/26542080); Rate: 2131884/sec for 1.000028115s; Time left (est.): 11s Processing: 16% (4292163/26542080); Rate: 2160219/sec for 1.000087826s; Time left (est.): 10s Processing: 24% (6438334/26542080); Rate: 2146157/sec for 1.000017364s; Time left (est.): 9s Processing: 32% (8529362/26542080); Rate: 2090965/sec for 1.000367121s; Time left (est.): 8s Processing: 40% (10737065/26542080); Rate: 2207530/sec for 1.000072427s; Time left (est.): 7s Processing: 48% (12958905/26542080); Rate: 2221755/sec for 1.000003187s; Time left (est.): 6s Processing: 57% (15163877/26542080); Rate: 2204929/sec for 1.000002717s; Time left (est.): 5s Processing: 65% (17254760/26542080); Rate: 2090742/sec for 1.00008452s; Time left (est.): 4s Processing: 73% (19513142/26542080); Rate: 2258348/sec for 1.000071076s; Time left (est.): 3s Processing: 82% (21795213/26542080); Rate: 2282028/sec for 1.000076024s; Time left (est.): 2s Processing: 90% (24048891/26542080); Rate: 2253645/sec for 1.000146957s; Time left (est.): 1s Processing: 98% (26226252/26542080); Rate: 2177215/sec for 1.000129955s; Time left (est.): 0s Processing: 100% (26542080/26542080); Rate: 315792/sec for 1.000105149s; Time left (est.): 0s Validated solutions (13.001683829s) Solution #1: ╔═══════════╗ ║769│154│832╢ ║154│832│769╢ ║832│769│154╢ ╟───┼───┼───╢ ║671│945│328╢ ║945│328│671╢ ║328│671│945╢ ╟───┼───┼───╢ ║597│416│283╢ ║416│283│597╢ ║283│597│416╢ ╚═══════════╝ ``` ## Caveats While this may very well solve all possible Sudoku puzzles (including the one [designed against brute force algorithms](https://en.wikipedia.org/wiki/Sudoku_solving_algorithms)), the blanks in the puzzle, the harder it is, the more possible solutions there are, the more solutions it needs to parse, the longer it takes. As this is a computational heavy program, the more CPU you throw against it the faster it will solve issues. ## Generating your own blocks To generate your own blocks, you could use the following code: ```go func (solver *Solver) generate_blocks() []int { var blocks []int decvals := [9]int{49, 50, 51, 52, 53, 54, 55, 56, 57} for counter := 123456789; counter <= 987654321; counter++ { // Convert number to string ([]byte) digits := strconv.Itoa(counter) // Check if every number is only represented only once var valid bool valid = true for decval := range decvals { var count int for digit := range digits { if digits[digit] == byte(decvals[decval]) { count = count + 1 } } if count != 1 { valid = false } } if valid { blocks = append(blocks, counter) } } return blocks } ```