1 files changed, 100 insertions, 0 deletions

diff --git a/src/solvers/h48/stats.h b/src/solvers/h48/stats.h
new file mode 100644
index 0000000..6e78ab5
--- /dev/null
+++ b/src/solvers/h48/stats.h
@@ -0,0 +1,100 @@
+/*
+The h48stats solver computes how many moves it takes to solve to
+each of the 12 h48 coordinates, one for each value of h from 0 to 11.
+The solutions array is filled with the length of the solutions. The
+solutions array is therefore not a printable string.
+*/
+
+typedef struct {
+        cube_t cube;
+        int8_t nmoves;
+        int8_t depth;
+        uint8_t moves[MAXLEN];
+        uint32_t *cocsepdata;
+        uint8_t *h48data;
+        char *s;
+} dfsarg_solveh48stats_t;
+
+STATIC int64_t solve_h48stats_dfs(dfsarg_solveh48stats_t *);
+STATIC int64_t solve_h48stats(cube_t, int8_t, const void *, char [static 12]);
+
+STATIC int64_t
+solve_h48stats_dfs(dfsarg_solveh48stats_t *arg)
+{
+        const int64_t limit = 11;
+
+        int8_t bound, u;
+        uint8_t m;
+        uint32_t d;
+        int64_t coord, h;
+        dfsarg_solveh48stats_t nextarg;
+
+        /* Check cocsep lower bound (corners only) */
+        bound = get_h48_cdata(arg->cube, arg->cocsepdata, &d);
+        if (bound + arg->nmoves > arg->depth)
+                return 0;
+
+        /* Check h48 lower bound for h=0 (esep, but no eo) */
+        coord = coord_h48_edges(arg->cube, COCLASS(d), TTREP(d), 0);
+        bound = get_h48_bound(arg->cube, d, 0, 4, arg->h48data);
+        if (bound + arg->nmoves > arg->depth)
+                return 0;
+        
+        /* Update all other values, if solved */
+        coord = coord_h48_edges(arg->cube, COCLASS(d), TTREP(d), 11);
+        for (h = 0; h <= limit; h++) {
+                u = coord >> (11-h) == 0 && arg->s[h] == 99;
+                arg->s[h] = u * arg->nmoves + (1-u) * arg->s[h];
+        }
+
+        if (arg->s[limit] != 99)
+                return 0;
+
+        nextarg = *arg;
+        nextarg.nmoves = arg->nmoves + 1;
+        for (m = 0; m < 18; m++) {
+                nextarg.moves[arg->nmoves] = m;
+                if (!allowednextmove(nextarg.moves, nextarg.nmoves)) {
+                        /* If a move is not allowed, neither are its 180
+                         * and 270 degree variations */
+                        m += 2;
+                        continue;
+                }
+                nextarg.cube = move(arg->cube, m);
+                solve_h48stats_dfs(&nextarg);
+        }
+
+        return 0;
+}
+
+STATIC int64_t
+solve_h48stats(
+        cube_t cube,
+        int8_t maxmoves,
+        const void *data,
+        char solutions[static 12]
+)
+{
+        int i;
+        dfsarg_solveh48stats_t arg;
+
+        arg = (dfsarg_solveh48stats_t) {
+                .cube = cube,
+                .cocsepdata = get_cocsepdata_ptr(data),
+                .h48data = get_h48data_ptr(data),
+                .s = solutions
+        };
+
+        for (i = 0; i < 12; i++)
+                solutions[i] = (char)99;
+
+        for (arg.depth = 0;
+             arg.depth <= maxmoves && solutions[11] == 99;
+             arg.depth++)
+        {
+                arg.nmoves = 0;
+                solve_h48stats_dfs(&arg);
+        }
+
+        return 0;
+}