Camden Dixie O'Brien
f51e9a06b0
- Bits 0-8 are the possible values - Bits 9-12 is the concrete value - Bit 15 is 1 if the cell is determined
76 lines
1.9 KiB
C
76 lines
1.9 KiB
C
/*
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* Copyright (C) 2022 Camden Dixie O'Brien
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public
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* License along with this program. If not, see
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* <https://www.gnu.org/licenses/>.
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*/
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#ifndef SUD_H
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#define SUD_H
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#include <stdbool.h>
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#include <stdint.h>
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#define SEGLEN 3
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#define NDIGITS 9
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#define NCELLS 81
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#define DETMASK 0x8000
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#define VALSHIFT 9
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#define VALMASK 0x1e00
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#define DET(x) (x & DETMASK)
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#define VAL(x) ((x & VALMASK) >> VALSHIFT)
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struct sudoku {
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uint16_t cells[NDIGITS][NDIGITS];
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};
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enum update_res { NOT_ALLOWED, ALREADY_DET, OK };
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enum check_res { INCOMPLETE, INCORRECT, SOLVED };
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/**
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* Read `NCELLS` values from the given pointer and load them into the
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* sudoku.
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*/
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bool load(struct sudoku *sud, const char *ptr);
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/**
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* Attempt to update the cell at row `r`, column `c` to have the value
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* `val`. Returns `OK` on success, `ALREADY_DET` if the cell is
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* already determined or `NOT_ALLOWED` if the cell being `val` would
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* violate the sudoku rules.
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*/
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enum update_res
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update(struct sudoku *sud, unsigned r, unsigned c, unsigned val);
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/**
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* Print a string representation of the sudoku to stdout.
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*/
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void print(const struct sudoku *sud);
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/**
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* Determine whether the sudoku has been solved correctly, contains
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* invalid choices or is incomplete.
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*/
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enum check_res check(const struct sudoku *sud);
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/**
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* Determine whether all the sudoku's cells have been determined.
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*/
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bool filled(const struct sudoku *sud);
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#endif
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