Attempt at A*, have to review notes

Co-authored-by: sigonasr2 <sigonasr2@gmail.com>

main.cpp

@@ -4,62 +4,25 @@
 
 using namespace olc;
 
-std::vector<int> validPathStepCounts;
+struct node{
+    char elevation='a';
+    bool visited=false;
+    std::vector<node*>connections;
+    int myDist=INFINITY;
+    int storedDist=INFINITY;
+    vi2d pos;
+    node*parent=nullptr;
+    node(char elevation){
+        this->elevation=elevation;
+    };
+};
+
+
 vi2d playerPos={0,0};
 vi2d endingPos={0,0};
-std::vector<std::vector<char>>grid;
-int lowest=2468;
-
-void step(char currentTile,vi2d pos,int xoffset,int yoffset,int stepCount,std::vector<std::vector<char>>visitedgrid,std::string currentPath){
-    pos.x+=xoffset;
-    pos.y+=yoffset;
-    std::cout<<currentPath<<std::endl;
-    if (currentTile=='S'){
-        currentTile='a';
-    }
-    if (stepCount+abs(pos.x-endingPos.x)+abs(pos.y-endingPos.y)>lowest){
-        //std::cout<<"Took too long..."<<std::endl;
-        return;
-    }
-    if (pos.y<0||pos.x<0||pos.x>=visitedgrid[0].size()||pos.y>=visitedgrid.size()){
-        //std::cout<<"Dead end reached in "<<stepCount<<" steps ("<<currentPath<<")"<<std::endl;
-        return;
-    }
-    if (visitedgrid[pos.y][pos.x]!='0'&&(visitedgrid[pos.y][pos.x]!='E'&&visitedgrid[pos.y][pos.x]-currentTile<=1||visitedgrid[pos.y][pos.x]=='E'&&currentTile>='y')){
-        currentPath+=visitedgrid[pos.y][pos.x];
-        if (visitedgrid[pos.y][pos.x]=='E'){
-            validPathStepCounts.push_back(++stepCount);
-            if (stepCount<lowest){
-                lowest=stepCount;
-                std::cout<<"Valid path found in "<<stepCount<<" steps! ("<<currentPath<<")"<<std::endl;
-            }
-            return;
-        }
-        ++stepCount;
-        char newTile=visitedgrid[pos.y][pos.x];
-        visitedgrid[pos.y][pos.x]='0';
-        if (pos.y+1<visitedgrid.size()&&visitedgrid[pos.y+1][pos.x]!='0'&&yoffset!=-1){
-            //visitedgrid[pos.y+1][pos.x]='0';
-            std::vector<std::vector<char>>newvisitedgrid=visitedgrid;
-            step(newTile,pos,0,1,stepCount,newvisitedgrid,currentPath);
-        }
-        if (pos.y-1>=0&&visitedgrid[pos.y-1][pos.x]!='0'&&yoffset!=1){
-            //visitedgrid[pos.y-1][pos.x]='0';
-            std::vector<std::vector<char>>newvisitedgrid=visitedgrid;
-            step(newTile,pos,0,-1,stepCount,newvisitedgrid,currentPath);
-        }
-        if (pos.x-1>=0&&visitedgrid[pos.y][pos.x-1]!='0'&&xoffset!=1){
-            //visitedgrid[pos.y][pos.x-1]='0';
-            std::vector<std::vector<char>>newvisitedgrid=visitedgrid;
-            step(newTile,pos,-1,0,stepCount,newvisitedgrid,currentPath);
-        }
-        if (pos.x+1<visitedgrid[0].size()&&visitedgrid[pos.y][pos.x+1]!='0'&&xoffset!=-1){
-            //visitedgrid[pos.y][pos.x+1]='0';
-            std::vector<std::vector<char>>newvisitedgrid=visitedgrid;
-            step(newTile,pos,1,0,stepCount,newvisitedgrid,currentPath);
-        }
-    }
-}
+std::vector<std::vector<node>>grid;
+node*startNode;
+node*endNode;
 
 int main()
 {
@@ -67,10 +30,10 @@ int main()
     while (file.good()){
         std::string line;
         std::getline(file,line);
-        std::vector<char>row;
+        std::vector<node>row;
         if (line.length()>0){
             for (int x=0;x<line.length();x++){
-                row.push_back(line[x]);
+                row.push_back(node(line[x]));
                 if (line[x]=='S'){
                     playerPos={x,(int)grid.size()};
                 }
@@ -85,30 +48,75 @@ int main()
     std::cout<<"================"<<std::endl;
     for (int y=0;y<grid.size();y++){
         for (int x=0;x<grid[y].size();x++){
-            std::cout<<grid[y][x];
+            std::cout<<grid[y][x].elevation;
+            grid[y][x].pos={x,y};
+            if (x>0){
+                grid[y][x].connections.push_back(&grid[y][x-1]);
+            }
+            if (x<grid[y].size()-1){
+                grid[y][x].connections.push_back(&grid[y][x+1]);
+            }
+            if (y>0){
+                grid[y][x].connections.push_back(&grid[y-1][x]);
+            }
+            if (y<grid.size()-1){
+                grid[y][x].connections.push_back(&grid[y+1][x]);
+            }
+            if (x==playerPos.x&&y==playerPos.y){
+                startNode=&grid[y][x];
+                std::cout<<"Starting node set."<<std::endl;
+            }
+            if (x==endingPos.x&&y==endingPos.y){
+                endNode=&grid[y][x];
+                std::cout<<"Ending node set."<<std::endl;
+            }
         }
         std::cout<<std::endl;
     }
-    std::cout<<"Player Pos: "<<playerPos<<std::endl;
-    char newTile=grid[playerPos.y][playerPos.x];
-    grid[playerPos.y][playerPos.x]='0';
-    std::vector<std::vector<char>>visitedgrid=grid;
-    std::vector<std::vector<char>>visitedgrid2=grid;
-    std::vector<std::vector<char>>visitedgrid3=grid;
-    std::vector<std::vector<char>>visitedgrid4=grid;
-    std::cout<<"Part 1"<<std::endl;
-    step(newTile,playerPos,1,0,0,visitedgrid,"S");
-    std::cout<<"Part 2"<<std::endl;
-    step(newTile,playerPos,-1,0,0,visitedgrid2,"S");
-    std::cout<<"Part 3"<<std::endl;
-    step(newTile,playerPos,0,1,0,visitedgrid3,"S");
-    std::cout<<"Part 4"<<std::endl;
-    step(newTile,playerPos,0,-1,0,visitedgrid4,"S");
-    std::sort(validPathStepCounts.begin(),validPathStepCounts.end());
-    for (int i=0;i<validPathStepCounts.size();i++){
-        std::cout<<validPathStepCounts[i]<<std::endl;
-    }
-    std::cout<<"Best: "<<validPathStepCounts[0]<<std::endl;
+
+    std::vector<node*>searchNodes;
+    searchNodes.push_back(startNode);
+    while (searchNodes.size()>0){
+        node*currentNode=searchNodes.front();
+        if (currentNode==startNode){
+            currentNode->myDist=pow(currentNode->pos.x-endNode->pos.x,2)+pow(currentNode->pos.y-endNode->pos.y,2);
+        }
+        currentNode->visited=true;
+        if (currentNode->elevation=='S'){
+            currentNode->elevation='a'-1;
+        }
+        if (currentNode->elevation=='E'){
+            currentNode->elevation='z'+1;
+        }
+        for (int i=0;i<currentNode->connections.size();i++){
+            node*neighbor=currentNode->connections[i];
+            if (neighbor==endNode){
+                //We can't go any higher.
+                endNode->parent=currentNode;
+                break;
+            }
+            if (neighbor->elevation-1<=currentNode->elevation){
+                if (neighbor->parent==nullptr||currentNode->myDist<neighbor->storedDist){
+                    neighbor->parent=currentNode;
+                    neighbor->storedDist=currentNode->myDist;
+                    neighbor->myDist=pow(neighbor->pos.x-endNode->pos.x,2)+pow(neighbor->pos.y-endNode->pos.y,2);
+                    if (!neighbor->visited){
+                        searchNodes.push_back(neighbor);
+                    }
+                }
+            }
+        }
+        searchNodes.erase(searchNodes.begin());
+    }
+
+    node*searchNode=endNode;
+    int jumps=0;
+    while (searchNode!=startNode){
+        std::cout<<"Node goes from "<<searchNode->pos<<" to "<<searchNode->parent->pos<<std::endl;
+        jumps++;
+        searchNode=searchNode->parent;
+    }
+    std::cout<<"Shortest path is "<<jumps<<" hops"<<std::endl;
 
 	return 0;
 }