Finish day 10 part 2!

Day 10/main.cpp

@@ -1,7 +1,7 @@
 #pragma region Hidden Setup Stuff
 #define OLC_PGE_APPLICATION
 #include "olcPixelGameEngine.h"
-
+#include <optional>
 using namespace olc;
 
 enum Run{
@@ -46,18 +46,21 @@ struct Pipe{
 
 std::vector<std::vector<Pipe>>tiles;
 
+std::vector<vi2d>pipeEdges;
+
 vi2d startingPipe;
 
+int tileCounts=0;
+
 std::optional<Pipe*>GetPipe(vi2d coords){
 	if(coords.x<0||coords.y<0||coords.y>=tiles.size()||coords.x>=tiles[coords.y].size())return {};
 	return &tiles[coords.y][coords.x];
 }
 
-std::vector<vi2d>tilesRemaining;
-
 void MarkAndMove(vi2d&pos,Direction dir){
 	tiles[pos.y][pos.x].partOfLoop=true;
 	tiles[pos.y][pos.x].traversed=true;
+	pipeEdges.push_back(pos);
 	switch(dir){
 		case UP:{
 			pos.y-=1;
@@ -112,6 +115,41 @@ void AddPipe(std::string row1,std::string row2,std::string row3,std::vector<Pipe
 	}
 }
 
+bool HitEdge(vi2d coord,Direction dir){
+	while(true){
+		switch(dir){
+			case DOWN:coord+={0,1};break;
+			case UP:coord+={0,-1};break;
+			case RIGHT:coord+={1,0};break;
+			case LEFT:coord+={-1,0};break;
+		}
+		auto pipe=GetPipe(coord);
+		if(pipe){
+			if(pipe.value()->partOfLoop){
+				return false; //Hit one of our edge pipes.
+			}
+		}else{
+			return true;
+		}
+	}
+}
+
+void FloodFill(vi2d coord){
+	auto pipe=GetPipe(coord);
+	if(pipe&&!pipe.value()->partOfLoop&&!pipe.value()->originalChar!=' '){
+		pipe.value()->originalChar=' ';
+		auto downPipe=GetPipe(coord+vi2d{0,1});
+		if(downPipe&&!downPipe.value()->partOfLoop&&downPipe.value()->originalChar!=' ')FloodFill(coord+vi2d{0,1});
+		auto upPipe=GetPipe(coord+vi2d{0,-1});
+		if(upPipe&&!upPipe.value()->partOfLoop&&upPipe.value()->originalChar!=' ')FloodFill(coord+vi2d{0,-1});
+		auto leftPipe=GetPipe(coord+vi2d{-1,0});
+		if(leftPipe&&!leftPipe.value()->partOfLoop&&leftPipe.value()->originalChar!=' ')FloodFill(coord+vi2d{-1,0});
+		auto rightPipe=GetPipe(coord+vi2d{1,0});
+		if(rightPipe&&!rightPipe.value()->partOfLoop&&rightPipe.value()->originalChar!=' ')FloodFill(coord+vi2d{1,0});
+	}
+}
+	
+
 void doStuff2(){
 	while(true){ //lines is accessible as a global.
 		for(std::string&line:lines){
@@ -171,11 +209,14 @@ void doStuff2(){
 						throw;
 					}
 				}
+				tileCounts++;
 			}
 			tiles.push_back(upperRow);
 			tiles.push_back(middleRow);
 			tiles.push_back(lowerRow);
 		}
+
+		std::cout<<tileCounts<<std::endl;
 		
 		//tilesRemaining.push_back(startingPipe);
 		auto initialPipe=GetPipe(startingPipe);
@@ -207,10 +248,10 @@ void doStuff2(){
 
 		if(symbol=='\0')throw;
 
-		if(initialPipe.value()->down)tiles[startingPipe.y+2][startingPipe.x+1].originalChar=symbol;
+		if(initialPipe.value()->down){tiles[startingPipe.y+2][startingPipe.x+1].originalChar=symbol;tiles[startingPipe.y+2][startingPipe.x+1].partOfLoop=true;}
-		if(initialPipe.value()->right)tiles[startingPipe.y+1][startingPipe.x+2].originalChar=symbol;
+		if(initialPipe.value()->right){tiles[startingPipe.y+1][startingPipe.x+2].originalChar=symbol;tiles[startingPipe.y+1][startingPipe.x+2].partOfLoop=true;}
-		if(initialPipe.value()->up)tiles[startingPipe.y][startingPipe.x+1].originalChar=symbol;
+		if(initialPipe.value()->up){tiles[startingPipe.y][startingPipe.x+1].originalChar=symbol;tiles[startingPipe.y][startingPipe.x+1].partOfLoop=true;}
-		if(initialPipe.value()->left)tiles[startingPipe.y+1][startingPipe.x].originalChar=symbol;
+		if(initialPipe.value()->left){tiles[startingPipe.y+1][startingPipe.x].originalChar=symbol;tiles[startingPipe.y+1][startingPipe.x].partOfLoop=true;}
 		tiles[startingPipe.y+1][startingPipe.x+1].originalChar=symbol;
 
 		vi2d currentPos=startingPipe+vi2d{1,1};
@@ -243,6 +284,25 @@ void doStuff2(){
 		//Test runs in all directions of looped pipes, see if they hit outer walls.
 		//If they do, starting from the wall, flood fill all adjacent tiles.
 		
+		//Start at any other edge, traverse in all directions and try to find a way out.
+		for(vi2d&coord:pipeEdges){
+			//Try to draw a line going in all directions and see if we hit an edge.
+			vi2d tempCoord=coord;
+			if(HitEdge(coord,DOWN)){std::cout<<"Flood Fill from "<<coord+vi2d{0,1}<<std::endl;FloodFill(coord+vi2d{0,1});break;}
+			if(HitEdge(coord,UP)){std::cout<<"Flood Fill from "<<coord+vi2d{0,-1}<<std::endl;FloodFill(coord+vi2d{0,-1});break;}
+			if(HitEdge(coord,RIGHT)){std::cout<<"Flood Fill from "<<coord+vi2d{1,0}<<std::endl;FloodFill(coord+vi2d{1,0});break;}
+			if(HitEdge(coord,LEFT)){std::cout<<"Flood Fill from "<<coord+vi2d{-1,0}<<std::endl;FloodFill(coord+vi2d{-1,0});break;}
+		}
+
+		for(int y=0;y<tiles.size()/3;y++){
+			for(int x=0;x<tiles[y].size()/3;x++){
+				vi2d coords=vi2d{x,y}*3+vi2d{1,1};
+				if(tiles[coords.y][coords.x].originalChar==' '||tiles[coords.y][coords.x].partOfLoop)tileCounts--;
+			}
+		}
+
+		std::cout<<tileCounts<<std::endl;
+
 		wait(0);
 		break;
 		 //Wait for 0ms and render the screen (calls draw())
@@ -375,7 +435,7 @@ public:
 int main()
 {
 	AoC2023 game;
-	if (game.Construct(3360,3360, 2, 2))
+	if (game.Construct(480,480, 2, 2))
 		game.Start();
 	return 0;
 }