From a848d0fd96b4003cf9fd813239c417e3d09297ef Mon Sep 17 00:00:00 2001
From: i-vishi <rr.vishalgaur@gmail.com>
Date: Tue, 2 Oct 2018 02:15:19 +0530
Subject: [PATCH] Create checkBipartite.cpp

check bipartite graph using bfs
---
 checkBipartite.cpp | 61 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 checkBipartite.cpp

diff --git a/checkBipartite.cpp b/checkBipartite.cpp
new file mode 100644
index 0000000..c6bb6b9
--- /dev/null
+++ b/checkBipartite.cpp
@@ -0,0 +1,61 @@
+//Check whether a graph is bipartite or not
+
+#include<bits/stdc++.h>
+#define max 10000                                                   // Limit of vertices
+
+int mat[max][max];                                                  //Adjacency Matrix (to be taken as input)
+int bfsQ[max];                                                      //Queue for BFS
+int r = -1;
+int f = 0;
+bool bfsVisited[max];                                               //Visited array for vertices
+bool color[max];                                                    //Color array for vertices
+
+void makeBFS(int v, int n){                                         //make bfs and assign alternate colors to vertices
+  for(int i=0;i<n;i++){
+    if(mat[v][i] && !bfsVisited[i]){
+      bfsQ[++r] = i;
+      color[i] = !color[v];
+    }
+  }
+    if(f <= r){
+      bfsVisited[bfsQ[f]] = true;
+      makeBFS(bfsQ[f++], n);
+  }
+}
+
+bool checkBipartite(int n){                                         //check bipartite using 2-colored theorem
+  bool result = true;
+  int i;
+  for(i=0;i<max;i++){
+      bfsQ[i]=0;
+      bfsVisited[i]=false;
+  }
+  color[0] = true;
+  makeBFS(0,n);
+  for(int i=0;i<n;i++){
+    for(int j=0;j<n;j++){
+      if(mat[i][j] == 1 && color[i] == color[j]){
+        result = false;
+        break;
+      }
+    }
+  }
+  return result;
+}
+
+using namespace std;
+
+int main(){
+  int n;
+  cout<<"Enter number of vertices : ";
+  cin>>n;
+  cout<<"Enter adjacency matrix: \n";
+  for(int i=0;i<n;i++){
+    for(int j=0;j<n;j++){
+      cin>>mat[i][j];
+    }
+  }
+  bool ch = checkBipartite(n);
+  cout<<boolalpha<<"\n Is the graph a Bipartite Graph? : \t"<<ch<<endl;
+  return 0;
+}