339 lines
10 KiB
C
339 lines
10 KiB
C
/* Warning: the function init_maze does not always return a maze with a solution */
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/* The current algorithm uses a self-avoiding random walk. A better option may be */
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/* to give random weights to the dual graph, and finite a maximal spanning tree */
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/* Change constant RAND_SHIFT to change the maze */
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typedef struct
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{
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short int nneighb; /* number of neighbours */
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int neighb[MAZE_MAX_NGBH]; /* neighbour cells */
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short int directions[MAZE_MAX_NGBH]; /* direction of neighbours */
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short int north, east, south, west; /* closed walls */
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short int active; /* takes value 1 if currently active in RW path */
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short int tested; /* takes value 1 if tested */
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short int connected; /* takes value 1 if connected to exit */
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short int closed; /* takes value 1 if no untested neighbours */
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} t_maze;
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int nmaze(int i, int j)
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{
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return(NXMAZE*j + i);
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}
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void init_maze_graph(t_maze maze[NXMAZE*NYMAZE])
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{
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int i, j, k, n;
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printf("Initializing maze\n");
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/* initialize neighbours */
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/* in the bulk */
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for (i=1; i<NXMAZE-1; i++)
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for (j=1; j<NYMAZE-1; j++)
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{
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n = nmaze(i, j);
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maze[n].nneighb = 4;
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maze[n].neighb[0] = nmaze(i, j+1);
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maze[n].neighb[1] = nmaze(i+1, j);
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maze[n].neighb[2] = nmaze(i, j-1);
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maze[n].neighb[3] = nmaze(i-1, j);
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for (k=0; k<4; k++) maze[n].directions[k] = k;
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}
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/* left side */
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for (j=1; j<NYMAZE-1; j++)
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{
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n = nmaze(0, j);
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maze[n].nneighb = 3;
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maze[n].neighb[0] = nmaze(0, j+1);
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maze[n].neighb[1] = nmaze(1, j);
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maze[n].neighb[2] = nmaze(0, j-1);
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for (k=0; k<3; k++) maze[n].directions[k] = k;
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}
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/* right side */
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for (j=1; j<NYMAZE-1; j++)
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{
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n = nmaze(NXMAZE-1, j);
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maze[n].nneighb = 3;
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maze[n].neighb[0] = nmaze(NXMAZE-1, j+1);
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maze[n].neighb[1] = nmaze(NXMAZE-2, j);
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maze[n].neighb[2] = nmaze(NXMAZE-1, j-1);
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maze[n].directions[0] = 0;
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maze[n].directions[1] = 3;
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maze[n].directions[2] = 2;
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}
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/* bottom side */
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for (i=1; i<NXMAZE-1; i++)
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{
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n = nmaze(i, 0);
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maze[n].nneighb = 3;
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maze[n].neighb[0] = nmaze(i, 1);
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maze[n].neighb[1] = nmaze(i+1, 0);
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maze[n].neighb[2] = nmaze(i-1, 0);
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maze[n].directions[0] = 0;
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maze[n].directions[1] = 1;
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maze[n].directions[2] = 3;
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}
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/* top side */
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for (i=1; i<NXMAZE-1; i++)
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{
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n = nmaze(i, NYMAZE-1);
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maze[n].nneighb = 3;
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maze[n].neighb[0] = nmaze(i, NYMAZE-2);
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maze[n].neighb[1] = nmaze(i+1, NYMAZE-1);
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maze[n].neighb[2] = nmaze(i-1, NYMAZE-1);
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maze[n].directions[0] = 2;
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maze[n].directions[1] = 1;
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maze[n].directions[2] = 3;
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}
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/* corners */
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n = nmaze(0,0);
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maze[n].nneighb = 2;
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maze[n].neighb[0] = nmaze(1,0);
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maze[n].neighb[1] = nmaze(0,1);
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maze[n].directions[0] = 1;
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maze[n].directions[1] = 0;
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n = nmaze(NXMAZE-1,0);
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maze[n].nneighb = 2;
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maze[n].neighb[0] = nmaze(NXMAZE-2,0);
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maze[n].neighb[1] = nmaze(NXMAZE-1,1);
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maze[n].directions[0] = 3;
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maze[n].directions[1] = 0;
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n = nmaze(0,NYMAZE-1);
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maze[n].nneighb = 2;
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maze[n].neighb[0] = nmaze(1,NYMAZE-1);
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maze[n].neighb[1] = nmaze(0,NYMAZE-2);
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maze[n].directions[0] = 1;
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maze[n].directions[1] = 2;
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n = nmaze(NXMAZE-1,NYMAZE-1);
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maze[n].nneighb = 2;
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maze[n].neighb[0] = nmaze(NXMAZE-2,NYMAZE-1);
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maze[n].neighb[1] = nmaze(NXMAZE-1,NYMAZE-2);
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maze[n].directions[0] = 3;
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maze[n].directions[1] = 2;
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/* initialize other parameters */
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for (i=0; i<NXMAZE; i++)
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for (j=0; j<NYMAZE; j++)
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{
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n = nmaze(i, j);
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maze[n].active = 0;
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maze[n].tested = 0;
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maze[n].connected = 0;
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maze[n].closed = 0;
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maze[n].north = 1;
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maze[n].east = 1;
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maze[n].south = 1;
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maze[n].west = 1;
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}
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}
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int find_maze_path(t_maze maze[NXMAZE*NYMAZE], int n0, int *path, int *pathlength)
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/* find a random walk path in the maze */
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/* returns 0 or 1 depending on whether path reaches a tested cell or a deadend */
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{
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int active_counter = 0, i, n = n0, npaths, inext, nextcell, trial, nnext, deadend = 1, length = 0;
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int next_table[4];
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/* contruct random walk */
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npaths = maze[n].nneighb;
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path[0] = n0;
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// while ((npaths > 0)&&(!maze[n].tested))
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while ((npaths > 0))
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{
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maze[n].active = 1;
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printf("Cell (%i, %i) ", n%NXMAZE, n/NXMAZE);
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nnext = 0;
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for (i=0; i<npaths; i++)
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{
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nextcell = maze[n].neighb[i];
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if ((!maze[nextcell].active)&&((maze[nextcell].connected)||(!maze[nextcell].tested)))
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{
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next_table[nnext] = i;
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nnext++;
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}
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}
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if (nnext == 0)
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{
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deadend = 1;
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printf("Ended path\n");
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// sleep(5);
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npaths = 0;
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maze[n].closed = 1;
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}
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else
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{
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deadend = 0;
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inext = next_table[rand()%nnext];
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nextcell = maze[n].neighb[inext];
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switch(maze[n].directions[inext]){
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case(0):
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{
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printf("Moving north\n");
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maze[n].north = 0;
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maze[nextcell].south = 0;
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break;
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}
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case(1):
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{
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printf("Moving east\n");
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maze[n].east = 0;
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maze[nextcell].west = 0;
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break;
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}
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case(2):
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{
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printf("Moving south\n");
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maze[n].south = 0;
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maze[nextcell].north = 0;
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break;
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}
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case(3):
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{
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printf("Moving west\n");
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maze[n].west = 0;
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maze[nextcell].east = 0;
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break;
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}
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}
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n = nextcell;
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if (maze[n].tested) npaths = 0;
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else npaths = maze[n].nneighb;
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active_counter++;
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if (length < NXMAZE*NYMAZE)
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{
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length++;
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path[length] = n;
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}
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deadend = 0;
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}
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}
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printf("Reached tested cell (%i, %i)\n", n%NXMAZE, n/NXMAZE);
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if (!maze[n].connected) deadend = 1;
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/* update cell status */
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for (n=0; n<NXMAZE*NYMAZE; n++) if (maze[n].active)
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{
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maze[n].active = 0;
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maze[n].tested = 1;
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}
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printf("Ended path\n");
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if (deadend) printf("Deadend\n");
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*pathlength = length;
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printf("Path length %i \n", length);
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return(deadend);
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// return(active_counter);
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}
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void init_maze_old(t_maze maze[NXMAZE*NYMAZE])
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/* init a maze */
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{
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int i, pathlength, *path;
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init_maze_graph(maze);
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for (i=0; i<RAND_SHIFT; i++) rand();
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for (i=0; i<NXMAZE*NYMAZE; i++) if (!maze[i].tested) find_maze_path(maze, i, path, &pathlength);
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}
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void init_maze(t_maze maze[NXMAZE*NYMAZE])
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/* init a maze with exit at (nx, ny) */
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{
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int i, j, n, deadend, pathlength, newpathlength;
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int *path, *newpath;
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path = (int *)malloc(2*NXMAZE*NYMAZE*sizeof(short int));
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newpath = (int *)malloc(2*NXMAZE*NYMAZE*sizeof(short int));
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init_maze_graph(maze);
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for (i=0; i<RAND_SHIFT; i++) rand();
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find_maze_path(maze, 0, path, &pathlength);
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for (n=0; n<pathlength; n++) maze[path[n]].connected = 1;
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for (i=0; i<NXMAZE*NYMAZE; i++) if ((!maze[i].tested)&&(!maze[i].connected))
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{
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deadend = find_maze_path(maze, i, path, &pathlength);
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if (!deadend) for (n=0; n<pathlength; n++) maze[path[n]].connected = 1;
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j = 0;
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printf("deadend = %i, pathlength = %i\n", deadend, pathlength);
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// while ((deadend)&&(j < pathlength))
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while (deadend)
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{
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j++;
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if (j > pathlength) j = 0;
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printf("j = %i\n", j);
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// while (deadend)
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if (!maze[path[j]].connected) deadend = find_maze_path(maze, path[j], newpath, &newpathlength);
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if (!deadend) for (n=0; n<newpathlength; n++) maze[newpath[n]].connected = 1;
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}
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// for (n=0; n<newpathlength; n++) maze[newpath[n]].connected = 1;
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for (j=0; j<NXMAZE*NYMAZE; j++) if (maze[j].tested) maze[j].connected = 1;
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}
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free(path);
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free(newpath);
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}
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void init_maze_exit(int nx, int ny, t_maze maze[NXMAZE*NYMAZE])
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/* init a maze with exit at (nx, ny) */
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{
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int i, j, n, deadend, pathlength, newpathlength;
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int *path, *newpath;
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path = (int *)malloc(2*NXMAZE*NYMAZE*sizeof(short int));
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newpath = (int *)malloc(2*NXMAZE*NYMAZE*sizeof(short int));
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init_maze_graph(maze);
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for (i=0; i<RAND_SHIFT; i++) rand();
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find_maze_path(maze, nmaze(nx, ny), path, &pathlength);
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for (n=0; n<pathlength; n++) maze[path[n]].connected = 1;
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for (i=0; i<NXMAZE*NYMAZE; i++) if ((!maze[i].tested)&&(!maze[i].connected))
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{
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deadend = find_maze_path(maze, i, path, &pathlength);
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if (!deadend) for (n=0; n<pathlength; n++) maze[path[n]].connected = 1;
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j = 0;
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printf("deadend = %i, pathlength = %i\n", deadend, pathlength);
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// while ((deadend)&&(j < pathlength))
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while (deadend)
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{
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j++;
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if (j > pathlength) j = 0;
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printf("j = %i\n", j);
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// while (deadend)
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if (!maze[path[j]].connected) deadend = find_maze_path(maze, path[j], newpath, &newpathlength);
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if (!deadend) for (n=0; n<newpathlength; n++) maze[newpath[n]].connected = 1;
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}
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// for (n=0; n<newpathlength; n++) maze[newpath[n]].connected = 1;
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for (j=0; j<NXMAZE*NYMAZE; j++) if (maze[j].tested) maze[j].connected = 1;
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}
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free(path);
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free(newpath);
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}
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