From 627115b3368f38e45f9a2b0928cab0ad8d790cf4 Mon Sep 17 00:00:00 2001 From: Ritik2604 <49342895+Ritik2604@users.noreply.github.com> Date: Fri, 22 May 2020 16:23:41 +0530 Subject: [PATCH] Created Graph Algos it contains Dijkstra, Prims, dft, bft, dfs, bfs and many more. --- DataStructures/Graphs/GraphAlgos | 437 +++++++++++++++++++++++++++++++ 1 file changed, 437 insertions(+) create mode 100644 DataStructures/Graphs/GraphAlgos diff --git a/DataStructures/Graphs/GraphAlgos b/DataStructures/Graphs/GraphAlgos new file mode 100644 index 000000000..780a73e45 --- /dev/null +++ b/DataStructures/Graphs/GraphAlgos @@ -0,0 +1,437 @@ +import java.util.ArrayList; +import java.util.HashMap; +import java.util.LinkedList; +import Heaps.GenericHeap; +public class Graph { + private class vertex{ + HashMap nbrs=new HashMap<>(); + } + HashMap vertcs; + public Graph(){ + vertcs=new HashMap<>(); + } + public int numVertex() { + return this.vertcs.size(); + } + public boolean containsVertex(String vname) { + return this.vertcs.containsKey(vname); + } + public void addVertex(String vname) { + + vertex vtx=new vertex(); + this.vertcs.put(vname,vtx); + } + public void removeVertex(String vname) { + vertex vtx=this.vertcs.get(vname); + ArrayList keys=new ArrayList<>(vtx.nbrs.keySet()); + for(String key:keys) { + vertex nbrvtx=this.vertcs.get(key); + nbrvtx.nbrs.remove(vname); + } + this.vertcs.remove(vname); + } + + public int numEdge() { + int count=0; + ArrayList keys=new ArrayList<>(this.vertcs.keySet()); + for(String key:keys) { + vertex vtx=this.vertcs.get(key); + count+=vtx.nbrs.size(); + } + return count/2; + } + public boolean containsEdge(String vname1,String vname2) { + vertex vtx1=this.vertcs.get(vname1); + vertex vtx2=this.vertcs.get(vname2); + if(vtx1==null||vtx2==null||!vtx1.nbrs.containsKey(vname2)) + return false; + return true; + } + public void addEdge(String vname1,String vname2,int cost) { + vertex vtx1=this.vertcs.get(vname1); + vertex vtx2=this.vertcs.get(vname2); + if(vtx1==null||vtx2==null||vtx1.nbrs.containsKey(vname2)) + return; + vtx1.nbrs.put(vname2,cost); + vtx2.nbrs.put(vname1,cost); + } + public void removeEdge(String vname1,String vname2) { + vertex vtx1=this.vertcs.get(vname1); + vertex vtx2=this.vertcs.get(vname2); + if(vtx1==null||vtx2==null||!vtx1.nbrs.containsKey(vname2)) + return; + vtx1.nbrs.remove(vname2); + vtx2.nbrs.remove(vname1); + } + + public void display() { + ArrayList keys=new ArrayList<>(this.vertcs.keySet()); + for(String key:keys) { + vertex vtx=this.vertcs.get(key); + System.out.println(key+" := "+vtx.nbrs); + } + } + + public boolean hasPath(String source ,String dest,HashMap processed) { + processed.put(source, true); + if(containsEdge(source,dest)) { + return true; + } + vertex vtx=this.vertcs.get(source); + ArrayList keys=new ArrayList<>(vtx.nbrs.keySet()); + for(String key:keys) { + if(!processed.containsKey(key) && hasPath(key,dest,processed)) + return true; + } + return false; + + } + private class pair{ + String vname; + String psf; + } + public boolean bfs(String source,String dest) { // breadth first search + HashMap processed=new HashMap<>(); + + LinkedList queue=new LinkedList<>(); + pair sp=new pair(); + sp.vname=source; + sp.psf=source; + queue.addLast(sp); + + while(!queue.isEmpty()) { + pair rp=queue.removeFirst(); + if(processed.containsKey(rp.vname)) + continue; + processed.put(rp.vname,true); + + if(containsEdge(rp.vname,dest)) { + System.out.println(rp.psf+dest); + return true; + } + vertex vtx=this.vertcs.get(rp.vname); + ArrayList nbrs=new ArrayList<>(vtx.nbrs.keySet()); + for(String nbr:nbrs) { + if(!processed.containsKey(nbr)) { + pair np=new pair(); + np.vname=nbr; + np.psf=rp.psf+nbr; + queue.addLast(np); + } + } + } + return false; + } + public boolean dfs(String source,String dest) { //deapth first search + LinkedList stack=new LinkedList<>(); + HashMap processed=new HashMap<>(); + pair sp=new pair(); + sp.vname=source; + sp.psf=source; + stack.addFirst(sp); + while(!stack.isEmpty()) { + pair rp=stack.removeFirst(); + if(processed.containsKey(rp.vname)) + continue; + processed.put(rp.vname,true); + if(containsEdge(rp.vname,dest)) { + System.out.println(rp.psf+dest); + return true; + } + vertex vtx=this.vertcs.get(rp.vname); + ArrayList nbrs=new ArrayList<>(vtx.nbrs.keySet()); + for(String nbr:nbrs) { + if(!processed.containsKey(nbr)) { + pair np=new pair(); + np.vname=nbr; + np.psf=rp.psf+nbr; + stack.addFirst(np); + } + } + + } + return false; + } + public void bft() { //breadth first traversal + HashMap processed=new HashMap<>(); + LinkedList queue=new LinkedList<>(); + ArrayList keys=new ArrayList<>(this.vertcs.keySet()); + for(String key:keys) { + if(processed.containsKey(key)) + continue; + pair sp=new pair(); + sp.vname=key; + sp.psf=key; + queue.addLast(sp); + + while(!queue.isEmpty()) { + pair rp=queue.removeFirst(); + if(processed.containsKey(rp.vname)) + continue; + processed.put(rp.vname,true); + + System.out.println(rp.vname+" via "+rp.psf); + + vertex vtx=this.vertcs.get(rp.vname); + ArrayList nbrs=new ArrayList<>(vtx.nbrs.keySet()); + for(String nbr:nbrs) { + if(!processed.containsKey(nbr)) { + pair np=new pair(); + np.vname=nbr; + np.psf=rp.psf+nbr; + queue.addLast(np); + } + } + } + } + } + public void dft() { //deapt first traversal + HashMap processed=new HashMap<>(); + LinkedList stack=new LinkedList<>(); + ArrayList keys=new ArrayList<>(this.vertcs.keySet()); + for(String key:keys) { + pair sp=new pair(); + sp.vname=key; + sp.psf=key; + stack.addFirst(sp); + + while(!stack.isEmpty()) { + pair rp=stack.removeFirst(); + if(processed.containsKey(rp.vname)) + continue; + processed.put(rp.vname,true); + + System.out.println(rp.vname+" via "+rp.psf); + + vertex vtx=this.vertcs.get(rp.vname); + ArrayList nbrs=new ArrayList<>(vtx.nbrs.keySet()); + for(String nbr:nbrs) { + if(!processed.containsKey(nbr)) { + pair np=new pair(); + np.vname=nbr; + np.psf=rp.psf+nbr; + stack.addFirst(np); + } + } + } + } + } + + + public boolean isCyclic() { + HashMap processed=new HashMap<>(); + LinkedList queue=new LinkedList<>(); + ArrayList keys=new ArrayList<>(this.vertcs.keySet()); + for(String key:keys) { + if(processed.containsKey(key)) + continue; + pair sp=new pair(); + sp.vname=key; + sp.psf=key; + queue.addLast(sp); + + while(!queue.isEmpty()) { + pair rp=queue.removeFirst(); + if(processed.containsKey(rp.vname)) + return true; + processed.put(rp.vname,true); + + vertex vtx=this.vertcs.get(rp.vname); + ArrayList nbrs=new ArrayList<>(vtx.nbrs.keySet()); + for(String nbr:nbrs) { + if(!processed.containsKey(nbr)) { + pair np=new pair(); + np.vname=nbr; + np.psf=rp.psf+nbr; + queue.addLast(np); + } + } + } + } + return false; + } + public boolean isConnected() { + int flag=0; + HashMap processed=new HashMap<>(); + LinkedList queue=new LinkedList<>(); + ArrayList keys=new ArrayList<>(this.vertcs.keySet()); + for(String key:keys) { + if(processed.containsKey(key)) + continue; + flag++; + pair sp=new pair(); + sp.vname=key; + sp.psf=key; + queue.addLast(sp); + + while(!queue.isEmpty()) { + pair rp=queue.removeFirst(); + if(processed.containsKey(rp.vname)) + continue; + processed.put(rp.vname,true); + + vertex vtx=this.vertcs.get(rp.vname); + ArrayList nbrs=new ArrayList<>(vtx.nbrs.keySet()); + for(String nbr:nbrs) { + if(!processed.containsKey(nbr)) { + pair np=new pair(); + np.vname=nbr; + np.psf=rp.psf+nbr; + queue.addLast(np); + } + } + } + } + if(flag>=2) + return false; + else + return true; + } + public boolean isTree() { + return !isCyclic()&&isConnected(); + } + public ArrayList> getConnectedComp() { + ArrayList> ans=new ArrayList<>(); + HashMap processed=new HashMap<>(); + LinkedList queue=new LinkedList<>(); + ArrayList keys=new ArrayList<>(this.vertcs.keySet()); + for(String key:keys) { + if(processed.containsKey(key)) + continue; + ArrayList subans=new ArrayList<>(); + pair sp=new pair(); + sp.vname=key; + sp.psf=key; + queue.addLast(sp); + + while(!queue.isEmpty()) { + pair rp=queue.removeFirst(); + if(processed.containsKey(rp.vname)) + continue; + processed.put(rp.vname,true); + + subans.add(rp.vname); + + vertex vtx=this.vertcs.get(rp.vname); + ArrayList nbrs=new ArrayList<>(vtx.nbrs.keySet()); + for(String nbr:nbrs) { + if(!processed.containsKey(nbr)) { + pair np=new pair(); + np.vname=nbr; + np.psf=rp.psf+nbr; + queue.addLast(np); + } + } + } + ans.add(subans); + } + return ans; + } + private class PrimsPair implements Comparable{ + String vname; + String acqvname; + int cost; + public int compareTo(PrimsPair o) { + return o.cost-this.cost; + } + + } + public Graph prims() { + HashMap map=new HashMap<>(); + GenericHeap heap=new GenericHeap<>(); + Graph mst=new Graph(); + for(String vrtx:this.vertcs.keySet()) { + PrimsPair np=new PrimsPair(); + np.acqvname=null; + np.vname=vrtx; + np.cost=Integer.MAX_VALUE; + heap.add(np); + map.put(vrtx, np); + } + while(!heap.isEmpty()) { + PrimsPair rp=heap.remove(); + map.remove(rp.vname); + + if(rp.acqvname==null) { + mst.addVertex(rp.vname); + }else { + mst.addVertex(rp.vname); + mst.addEdge(rp.vname, rp.acqvname, rp.cost); + } + + for(String nbr:this.vertcs.get(rp.vname).nbrs.keySet()) { + if(map.containsKey(nbr)) { + //old cost that is from diff path stored in map + int oc=map.get(nbr).cost; + // cost that present vname need cost to go to nbr + int nc=this.vertcs.get(rp.vname).nbrs.get(nbr); + if(nc{ + String vname; + String psf; + int cost; + public int compareTo(DijktsraPair o) { + return o.cost-this.cost; + } + + } + public HashMap Dijktsra(String source) { + HashMap map=new HashMap<>(); + GenericHeap heap=new GenericHeap<>(); + HashMap ans =new HashMap<>(); + for(String vrtx:this.vertcs.keySet()) { + DijktsraPair np=new DijktsraPair(); + np.psf=""; + np.vname=vrtx; + np.cost=Integer.MAX_VALUE; + if(vrtx==source) { + np.cost=0; + np.psf=source; + } + heap.add(np); + map.put(vrtx, np); + } + while(!heap.isEmpty()) { + DijktsraPair rp=heap.remove(); + map.remove(rp.vname); + + ans.put(rp.vname,rp.cost); + + for(String nbr:this.vertcs.get(rp.vname).nbrs.keySet()) { + if(map.containsKey(nbr)) { + //old cost that is from diff path stored in map + int oc=map.get(nbr).cost; + // cost that present vname need cost to go to nbr + int nc=rp.cost+this.vertcs.get(rp.vname).nbrs.get(nbr); + if(nc