Probably a solution to p985, passes debug

p985/p985.cpp

@@ -3,6 +3,7 @@
 #include <string>
 #include <queue>
 #include <utility>
+#include <sstream>
 
 using namespace std;
 
@@ -15,8 +16,8 @@ uint8_t the_matrix[500][500];
 V3 V2 V1 V0 E3 E2 E1 E0
 
 Vx: Visited in this phase, V0 is the first phase
-Ex: Edge in this direction, E0 is to the north during phase 0, E1 to the east during phase 0 etc
-    E0 is to the east during phase 1, E1 to the south during phase 1 etc
+Ex: Edge in this direction, E0 is to the north during phase 0, E1 to the west during phase 0 etc
+    E0 is to the east during phase 1, E1 to the north during phase 1 etc
 */
 
 struct Agent
@@ -29,9 +30,9 @@ struct Agent
 enum Direction
 {
     NORTH,
-    EAST,
+    WEST,
     SOUTH,
-    WEST
+    EAST,
 };
 
 bool check_dir(Agent smith, Direction dir)
@@ -45,44 +46,74 @@ int main()
     int width, height, steps;
     string str_in;
 
+	ostringstream debug_stream;
+
     queue<Agent> search_queue;
 
-    while(cin >> width >> height)
+    while(cin >> height >> width)
     {
         steps = 0;
 
         cin.ignore(1000, '\n');
 
-        cout << "Read width and height [" << width << "][" << height << "]\n";
+        debug_stream << "Read width and height [" << width << "][" << height << "]\n";
 
-        for(int x = 0; x < width; x++)
+        for(int y = 0; y < height; y++)
         {
-            for(int y = 0; y < height; y++)
+            for(int x = 0; x < width; x++)
             {
                 if(x == (width-1) && y == (height-1))
+				{
+					the_matrix[x][y] = 0;
                     continue;
+				}
 
                 getline(cin, str_in);
 
-                cout << "Read line: " << str_in << endl;
+                debug_stream << "Read line: " << str_in << endl;
 
-                the_matrix[x][y] = (str_in.find('N') != string::npos) ? 1 : 0;
-                the_matrix[x][y] |= (str_in.find('E') != string::npos) ? 2 : 0;
-                the_matrix[x][y] |= (str_in.find('S') != string::npos) ? 4 : 0;
-                the_matrix[x][y] |= (str_in.find('W') != string::npos) ? 8 : 0;
+                the_matrix[x][y] = (str_in.find('N') != string::npos) ? (1<<NORTH) : 0;
+                the_matrix[x][y] |= (str_in.find('E') != string::npos) ? (1<<EAST) : 0;
+                the_matrix[x][y] |= (str_in.find('S') != string::npos) ? (1<<SOUTH) : 0;
+                the_matrix[x][y] |= (str_in.find('W') != string::npos) ? (1<<WEST) : 0;
             }
         }
 
-        cout << "populated the graph" << endl;
+        debug_stream << "populated the graph" << endl;
         for(int x = 0; x < width; x++)
         {
             for(int y = 0; y < height; y++)
             {
-                cout << x << ", " << y << ": 0x" << std::hex << (int)the_matrix[x][y] << endl;
+                debug_stream << x << ", " << y << ": 0x" << std::hex << (int)the_matrix[x][y] << endl;
+
+				int phase = 4;
+				if(check_dir(Agent{x,y,phase}, NORTH))
+				{
+					debug_stream << "Arrow to NORTH" << endl;
+				}
+
+				if(check_dir(Agent{x,y,phase}, EAST))
+				{
+					debug_stream << "Arrow to EAST" << endl;
+				}
+
+				if(check_dir(Agent{x,y,phase}, SOUTH))
+				{
+					debug_stream << "Arrow to SOUTH" << endl;
+				}
+
+				if(check_dir(Agent{x,y,phase}, WEST))
+				{
+					debug_stream << "Arrow to WEST" << endl;
+				}
             }
         }
 
-        // Start in upper right corner
+        // Clear queue
+		while(!search_queue.empty())
+			search_queue.pop();
+		
+		// Start in upper right corner
         search_queue.push(Agent{0,0,0});
 
         // Bredden först
@@ -91,41 +122,56 @@ int main()
             Agent smith = search_queue.front();
             search_queue.pop();
 
+			debug_stream << "Searching [" << smith.x << "][" << smith.y << "] during phase " << smith.steps%4 << " (step " << smith.steps << ")\n";
+
             if(smith.x == width-1 && smith.y == height-1)
             {
-                steps = smith.steps+1;
+				debug_stream << "Found exit!" << endl;
+                steps = smith.steps;
                 break;
             }
 
             if(the_matrix[smith.x][smith.y] & (0x10 << ((smith.steps)%4)))
             {
                 // Already visited
+				debug_stream << "Already visited" << endl;
                 continue;
             }
+			else
+			{
+				the_matrix[smith.x][smith.y] |= (0x10 << ((smith.steps)%4));
+			}
 
             if(smith.y != 0 && check_dir(smith, NORTH))
             {
+				debug_stream << "Possible to go NORTH" << endl;
                 search_queue.push(Agent{smith.x,smith.y-1,smith.steps+1});
             }
 
             if(smith.x != width-1 && check_dir(smith, EAST))
             {
-                search_queue.push(Agent{smith.x,smith.y+1,smith.steps+1});
+				debug_stream << "Possible to go EAST" << endl;
+                search_queue.push(Agent{smith.x+1,smith.y,smith.steps+1});
             }
 
             if(smith.y != height-1 && check_dir(smith, SOUTH))
             {
+				debug_stream << "Possible to go SOUTH" << endl;
                 search_queue.push(Agent{smith.x,smith.y+1,smith.steps+1});
             }
 
             if(smith.x != 0 && check_dir(smith, WEST))
             {
+				debug_stream << "Possible to go WEST" << endl;
                 search_queue.push(Agent{smith.x-1,smith.y,smith.steps+1});
             }
 
         }
 
-        cout << steps;
+		if(steps)
+			cout << steps << endl;
+		else
+			cout << "no path to exit" << endl;
 
     }