nqueens.h

/* nqueens.h
 *
 * (C) 2018 Eva Tuba <etuba@ieee.org> and Carlos M. Fonseca <cmfonsec@dei.uc.pt>
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or (at
 * your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */
 
/* Memory management */
struct solution *allocSolution(struct problem *p);
struct move *allocMove(struct problem *p);
struct pathState *allocPathState(struct problem *p);
 
void freeProblem(struct problem *p);
void freeSolution(struct solution *s);
void freeMove(struct move *v);
void freePathState(struct pathState *ps);
 
/* I/O */
void printProblem(struct problem *p);
void printSolution(struct solution *s);
void printMove(struct move *v);
void printPathState(struct pathState *ps);
 
/* Solution generation */
struct solution *randomSolution(struct solution *s);
 
/* Solution inspection */
double getObjectiveValue(struct solution *s);
 
/* Move generation */
struct move *randomMove(struct move *v, const struct solution *s);
 
/* Operations on solutions*/
struct solution *copySolution(struct solution *dest, const struct solution *src);
struct solution *applyMove(struct solution *s, const struct move *v);
 
/* Path generation */
struct pathState *initPathTo(struct pathState *ps, const struct solution *s1, const struct solution *s2);
struct pathState *initPathAwayFrom(struct pathState *ps, const struct solution *s);
struct move *nextRandomMove(struct move *v, struct pathState *ps);
 
/* Path inspection */
int getPathLength(const struct pathState *ps);
 
 
/* This header file contains all problem dependent definitions */
 
/* Problem-specific instantiation */
struct problem *newProblem(int n);
 
struct problem {
    int n;   /* number of queens */
};
 
struct solution {
    struct problem *prob;
    int *data;
    int *olddata;
    int *mod;       /* positions modified by moves */
    int *modi;      /* inverse permutation of mod */
    int nmod;       /* no. of positions modified since last evaluation */
    int n;
    int objvalue;
};
 
struct move {
    struct problem *prob;
    int data[2];
};
 
struct pathState{
    struct problem *prob;
    int *data;      /* normalised permutation computed as p2i[p1] */ 
    int *datai;     /* inverse permutation of data */ 
    int *cycle ;    /* number ot the cycle each element belons to */
    int *pos;       /* positions in which the solutions differ */
    int n;          /* number of queens / board size */
    int n_cycles;   /* number of cycles in data */
    int n_diff;     /* number of positions in which the solutions differ */
};