From 4c122225e5da529b620657b3e9a9a7e362bd38b7 Mon Sep 17 00:00:00 2001
From: Aishwarya Sah <aishwarya.asah@gmail.com>
Date: Wed, 9 Oct 2019 01:37:36 +0530
Subject: [PATCH] Added a matrix implementation code

---
 MatrixUsingBfsDfs.cpp | 205 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 205 insertions(+)
 create mode 100644 MatrixUsingBfsDfs.cpp

diff --git a/MatrixUsingBfsDfs.cpp b/MatrixUsingBfsDfs.cpp
new file mode 100644
index 0000000..c423a7d
--- /dev/null
+++ b/MatrixUsingBfsDfs.cpp
@@ -0,0 +1,205 @@
+/* 
+ Example program to reach from a starting given location to a final given destination
+ in a nXm matrix that is also given.
+ In the matrix, 1's specify a path that you can use from traversing
+*/
+#include <iostream>
+#include <string>
+#include<vector>
+#include<queue>
+#include<stack>
+using namespace std;
+
+//Class to encapsulate the coordinates and the minimum distance to reach from starting coordinates to this coordinate
+class path
+{
+    public:
+    int x;
+    int y;
+    int dist;
+};
+
+void bfs(vector<vector<int>> &matrix, int startx,int starty,int endx,int endy,int n,int m)
+{
+    //Object of the class to have the initial starting node
+    path p1;
+    p1.x=startx;
+    p1.y=starty;
+    p1.dist=0;
+    //Using queue because BFS uses queue
+    queue<path> q;
+    q.push(p1);
+    //Visited array is used to keep a track of the coordinates which have already been encountered
+    vector<vector<int>>visited(n ,vector<int>(m,0));
+
+    path d;
+    int flag=0,min_path=100;
+
+    while(!q.empty())
+    {
+        d=q.front();
+        q.pop();
+        //checking if we have reached the final destination
+        if(d.x==endx && d.y==endy)
+        {
+            flag=1;
+            if(d.dist < min_path)
+            {
+                min_path=d.dist;
+            }
+        }
+        else
+        {
+            path p2;
+            p2.dist=d.dist+1;
+            //Checking if the box below is in the matrix, has a path and has not been traversed till now.
+            if(((d.x+1)<n)&&(matrix[d.x+1][d.y]==1) && visited[d.x+1][d.y]==0)
+            {
+                p2.x=d.x+1;
+                p2.y=d.y;
+                q.push(p2);
+                visited[d.x+1][d.y]=1;
+            }
+            //Checking if the box above is in the matrix, has a path and has not been traversed till now.
+            if(((d.x-1)>=0)&&(matrix[d.x-1][d.y]==1) && visited[d.x-1][d.y]==0)
+            {
+                p2.x=d.x-1;
+                p2.y=d.y;
+                q.push(p2);
+                visited[d.x-1][d.y]=1;
+            }
+            //Checking if the box on the right is in the matrix, has a path and has not been traversed till now.
+            if(((d.y+1)<m)&&(matrix[d.x][d.y+1]==1) && visited[d.x][d.y+1]==0)
+            {
+                p2.x=d.x;
+                p2.y=d.y+1;
+                q.push(p2);
+                visited[d.x][d.y+1]=1;
+            }
+            //Checking if the box on the left is in the matrix, has a path and has not been traversed till now.            
+            if(((d.y-1)>=0)&&(matrix[d.x][d.y-1]==1)&& visited[d.x][d.y-1]==0)
+            {
+                p2.x=d.x;
+                p2.y=d.y-1;
+                q.push(p2);
+                visited[d.x][d.y-1]=1;
+            }
+        }
+    }
+    //If we were able to find a path then print the Minimum distance to reach there
+    if(flag==1)
+    {
+        cout<<"Minimum distance="<<min_path<<endl;
+    }
+    else
+    {
+        cout<<"Not possible to reach"<<endl;
+    }
+}
+
+void dfs(vector<vector<int>> &matrix, int startx,int starty,int endx,int endy,int n,int m)
+{
+    //Object of the class to have the initial starting node
+    path p1;
+    p1.x=startx;
+    p1.y=starty;
+    p1.dist=0;
+    //Using stack because DFS uses stack
+    stack<path> st;
+    st.push(p1);
+    //Visited array is used to keep a track of the coordinates which have already been encountered
+    vector<vector<int>>visited(n ,vector<int>(m,0));
+
+    path d;
+    int flag=0,min_path=100;
+
+    while(!st.empty())
+    {
+        d=st.top();
+        st.pop();
+        //checking if we have reached the final destination
+        if(d.x==endx && d.y==endy)
+        {
+            flag=1;
+            if(d.dist < min_path)
+            {
+                min_path=d.dist;
+            }
+        }
+        else
+        {
+            path p2;
+            p2.dist=d.dist+1;
+            //Checking if the box below is in the matrix, has a path and has not been traversed till now.
+            if(((d.x+1)<n)&&(matrix[d.x+1][d.y]==1) && visited[d.x+1][d.y]==0)
+            {
+                p2.x=d.x+1;
+                p2.y=d.y;
+                st.push(p2);
+                visited[d.x+1][d.y]=1;
+            }
+            //Checking if the box above is in the matrix, has a path and has not been traversed till now.
+            if(((d.x-1)>=0)&&(matrix[d.x-1][d.y]==1) && visited[d.x-1][d.y]==0)
+            {
+                p2.x=d.x-1;
+                p2.y=d.y;
+                st.push(p2);
+                visited[d.x-1][d.y]=1;
+            }
+            //Checking if the box on the right is in the matrix, has a path and has not been traversed till now.
+            if(((d.y+1)<m)&&(matrix[d.x][d.y+1]==1) && visited[d.x][d.y+1]==0)
+            {
+                p2.x=d.x;
+                p2.y=d.y+1;
+                st.push(p2);
+                visited[d.x][d.y+1]=1;
+            }
+            //Checking if the box on the left is in the matrix, has a path and has not been traversed till now.            
+            if(((d.y-1)>=0)&&(matrix[d.x][d.y-1]==1)&& visited[d.x][d.y-1]==0)
+            {
+                p2.x=d.x;
+                p2.y=d.y-1;
+                st.push(p2);
+                visited[d.x][d.y-1]=1;
+            }
+        }
+    }
+    //If we were able to find a path then print the Minimum distance to reach there
+    if(flag==1)
+    {
+        cout<<"Minimum distance="<<min_path<<endl;
+    }
+    else
+    {
+        cout<<"Not possible to reach"<<endl;
+    }
+}
+
+
+int main()
+{
+    int startx,starty,endx,endy,i,j,n,m,x;
+    vector<vector<int>>matrix;
+    // N= number of rows, M=number of columns
+    cin>>n>>m;
+    //startx and starty define the starting coordinates from the matrix
+    cin>>startx;
+    cin>>starty;
+    //endx and endy define the final destination coordinates from the matrix
+    cin>>endx;
+    cin>>endy;
+    //Taking the matrix as input where 1 deines the places where a path exists
+    for(i=0; i<n; i++)
+    {
+        vector<int>v;
+        for(j=0; j<m; j++)
+        {
+            cin>>x;
+            v.push_back(x);
+        }
+        matrix.push_back(v);
+    }
+    //bfs implementation
+    bfs(matrix, startx, starty, endx, endy,n,m);
+    dfs(matrix, startx, starty, endx, endy,n,m);
+}
\ No newline at end of file