From 44f17197a2d168b4e64b61ad3be9cdeb4fc554d4 Mon Sep 17 00:00:00 2001
From: ApurvGangavane <apurvdg22@gmail.com>
Date: Sun, 24 Oct 2021 00:18:50 +0530
Subject: [PATCH] Added Search in a Maze (Greedy) CPP solution

---
 C++/Search_in_a_Maze.cpp | 77 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 C++/Search_in_a_Maze.cpp

diff --git a/C++/Search_in_a_Maze.cpp b/C++/Search_in_a_Maze.cpp
new file mode 100644
index 0000000..7a97a78
--- /dev/null
+++ b/C++/Search_in_a_Maze.cpp
@@ -0,0 +1,77 @@
+/*
+ * Problem Statement -
+ Consider a rat placed at (0, 0) in a square matrix of order N * N.
+ It has to reach the destination at (N - 1, N - 1). Find all possible
+ paths that the rat can take to reach from source to destination. The
+ directions in which the rat can move are 'U'(up), 'D'(down), 'L' (left),
+ 'R' (right). Value 0 at a cell in the matrix represents that it is blocked
+ and rat cannot move to it while value 1 at a cell in the matrix represents
+ that rat can be travel through it.
+ Note: In a path, no cell can be visited more than one time.
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+class Solution{
+public:
+    void dfs(vector<vector<int>> &g, int i, int j, int n, vector<string> &result, string path){
+        // Here i is row and j is column
+        if(i < 0 || j < 0 || i >= n || j >= n || g[i][j] != 1 ){
+            return;
+        }
+
+        if( (i== n-1) && (j == n-1)){
+            result.push_back(path);
+            return;
+        }
+
+        g[i][j] = -1;
+        dfs(g, i+1, j, n, result, path+"D");
+        dfs(g, i, j+1, n, result, path+"R");
+        dfs(g, i-1, j, n, result, path+"U");
+        dfs(g, i-1, j-1, n, result, path+"L");
+        g[i][j] = 1;
+
+    }
+
+    vector<string> Search_Maze(vector<vector<int>> &graph, int n){
+        vector<string> result;
+        string ans = "";
+        dfs(graph, 0 , 0, n, result, ans);
+        sort(result.begin(), result.end());
+        return result;
+    }
+};
+
+int main() {
+    Solution obj;
+
+    int size;
+    cout<<"Enter size of N*N graph: ";
+    cin>>size;
+    cout<<endl;
+
+    vector<vector<int>> vec(size, (vector<int> (size, -1)));
+
+    cout<<"Enter elements of graph/Matrix: "<<endl;
+    for(int i=0; i<size; i++){
+        for(int j=0; j<size; j++){
+            cin>>vec[i][j];
+        }
+    }
+
+    vector<string> res = obj.Search_Maze(vec, size);
+
+    cout<<"Answer is: ";
+    if(res.size() == 0){
+        cout<< -1<<endl;
+    }else{
+        for(auto a: res){
+            cout<<a<<" ";
+        }
+        cout<<endl;
+    }
+
+    return 0;
+}