Fix state tracer

Signed-off-by: Artem Senichev <[email protected]>

src/cell.cpp

@@ -101,6 +101,20 @@ void Pipe::rotate(bool clockwise)
     }
 }
 
+std::vector<Side> Pipe::connections() const
+{
+    std::vector<Side> sides;
+    sides.reserve(Side::max);
+
+    for (const Side s : { Side::Top, Side::Right, Side::Bottom, Side::Left }) {
+        if (get(s)) {
+            sides.push_back(s);
+        }
+    }
+
+    return sides;
+}
+
 bool Pipe::get(const Side& side) const
 {
     return sides[side];

src/cell.hpp

@@ -5,6 +5,7 @@
 #pragma once
 
 #include <bitset>
+#include <vector>
 
 /** Position (coordinates). */
 struct Position {
@@ -58,6 +59,12 @@ class Pipe {
      */
     void rotate(bool clockwise);
 
+    /**
+     * Gat connection sides.
+     * @return array with connected sides
+     */
+    std::vector<Side> connections() const;
+
     /**
      * Check if side connected.
      * @param side to check

src/level.cpp

@@ -255,21 +255,33 @@ void Level::apply_path(const Position& start, const Level::Path& path)
     }
 }
 
-void Level::trace_state(const Position& pos)
+void Level::trace_state(const Position& start)
 {
-    Cell& cell = get_cell(pos);
-    const Side sides[] = { Side::Top, Side::Right, Side::Bottom, Side::Left };
-
-    for (const Side side : sides) {
-        if (cell.pipe.get(side)) {
-            const Position next_pos = neighbor(pos, side);
-            Cell& next_cell = get_cell(next_pos);
-            if (!next_cell.rotation() && !next_cell.active &&
-                next_cell.pipe.get(side.opposite())) {
-                next_cell.active = true;
-                trace_state(next_pos);
+    Position curr_pos = start;
+
+    while (true) {
+        Cell& curr_cell = get_cell(curr_pos);
+        curr_cell.active = true;
+
+        // get possible ways
+        std::vector<Position> connected;
+        for (const Side side : curr_cell.pipe.connections()) {
+            const Position next_pos = neighbor(curr_pos, side);
+            const Cell& next_cell = get_cell(next_pos);
+            if (next_pos != curr_pos && !next_cell.rotation() &&
+                !next_cell.active && next_cell.pipe.get(side.opposite())) {
+                connected.push_back(next_pos);
             }
         }
+        if (connected.empty()) {
+            break;
+        }
+
+        curr_pos = connected[0];
+
+        if (connected.size() > 1) { // fork
+            trace_state(connected[1]);
+        }
     }
 }