2 files changed, 58 insertions, 23 deletions

diff --git a/src/solvers/coord/solve.h b/src/solvers/coord/solve.h
index 6ddb9dd..9170cca 100644
--- a/src/solvers/coord/solve.h
+++ b/src/solvers/coord/solve.h
@@ -66,47 +66,83 @@ solve_coord_dfs_stop(const dfsarg_solve_coord_t arg[static 1])
 STATIC bool
 coord_continue_onnormal(const dfsarg_solve_coord_t arg[static 1])
 {
-        uint8_t f, nn, ni, th;
+        uint8_t flag, nn, ni, swbound_n, swbound_i;
 
-        f = arg->nissflag;
+        flag = arg->nissflag;
         nn = arg->solution_moves->nmoves;
         ni = arg->solution_moves->npremoves;
-        th = DIV_ROUND_UP(arg->target_depth, 2);
+        swbound_n = arg->target_depth / 2;
+        swbound_i = DIV_ROUND_UP(arg->target_depth, 2) - 1;
 
+        /* If only inverse moves are allowed */
+        if (flag == NISSY_NISSFLAG_INVERSE)
+                return false;
+        
+        /* It's the first move */
         if (nn + ni == 0)
-                return f & (NISSY_NISSFLAG_NORMAL | NISSY_NISSFLAG_MIXED);
+                return true;
+
+        if (arg->lastisnormal) {
+                /* Can continue if we have already switched */
+                if (ni > 0)
+                        return true;
 
-        /* TODO logic here can probably be simplified */
-        if (arg->lastisnormal)
-                return (f & NISSY_NISSFLAG_NORMAL) ||
-                    ((f & NISSY_NISSFLAG_MIXED) && (ni > 0 || nn <= th));
+                /* Check that we have enough moves left to switch */
+                return flag & NISSY_NISSFLAG_NORMAL || nn < swbound_n;
+        } else {
+                /* Forbid switching multiple times */
+                if (nn > 0)
+                        return false;
+
+                /* Some coordinates are not allowed to switch */
+                if (!coord_can_switch(arg->coord, arg->coord_data,
+                    ni, arg->solution_moves->premoves))
+                        return false;
 
-        return (f & NISSY_NISSFLAG_MIXED) && nn == 0 && ni < th &&
-            coord_can_switch(arg->coord, arg->coord_data,
-                ni, arg->solution_moves->premoves);
+                /* Only switch before half solution is found */
+                return ni <= swbound_i;
+        }
 }
 
 STATIC bool
 coord_continue_oninverse(const dfsarg_solve_coord_t arg[static 1])
 {
-        uint8_t f, nn, ni, th;
+        uint8_t flag, nn, ni, swbound_n, swbound_i;
 
-        f = arg->nissflag;
+        flag = arg->nissflag;
         nn = arg->solution_moves->nmoves;
         ni = arg->solution_moves->npremoves;
-        th = DIV_ROUND_UP(arg->target_depth, 2);
+        swbound_n = arg->target_depth / 2;
+        swbound_i = DIV_ROUND_UP(arg->target_depth, 2) - 1;
 
+        /* If only normal moves are allowed */
+        if (flag == NISSY_NISSFLAG_NORMAL)
+                return false;
+        
+        /* It's the first move */
         if (nn + ni == 0)
-                return f & (NISSY_NISSFLAG_INVERSE | NISSY_NISSFLAG_MIXED);
+                return true;
+
+        if (!arg->lastisnormal) {
+                /* Can continue if we have already switched */
+                if (nn > 0)
+                        return true;
 
-        /* TODO logic here can probably be simplified */
-        if (!arg->lastisnormal)
-                return (f & NISSY_NISSFLAG_INVERSE) ||
-                    ((f & NISSY_NISSFLAG_MIXED) && (nn > 0 || ni < th));
+                /* Check that we have enough moves left to switch */
+                return flag & NISSY_NISSFLAG_INVERSE || ni < swbound_i;
+        } else {
+                /* Forbid switching multiple times */
+                if (ni > 0)
+                        return false;
+
+                /* Some coordinates are not allowed to switch */
+                if (!coord_can_switch(arg->coord, arg->coord_data,
+                    nn, arg->solution_moves->moves))
+                        return false;
 
-        return (f & NISSY_NISSFLAG_MIXED) && ni == 0 && nn <= th &&
-            coord_can_switch(arg->coord, arg->coord_data,
-                nn, arg->solution_moves->moves);
+                /* Only switch before half solution is found */
+                return nn <= swbound_n;
+        }
 }
 
 STATIC int64_t
diff --git a/src/solvers/solutions.h b/src/solvers/solutions.h
index 0eb3a7f..00ed84c 100644
--- a/src/solvers/solutions.h
+++ b/src/solvers/solutions.h
@@ -233,7 +233,6 @@ appendsolution(
                 list->shortest_sol = MIN(
                     list->shortest_sol, tsol[r].nmoves + tsol[r].npremoves);
                 r++;
-
         }
 
         list->buf[list->used] = '\0';