#include <bits/stdc++.h>

using namespace std;
bool isSafe(vector<vector<int>>& m,int n,int x,int y,vector<vector<int>> v){
  if((x>=0 && x<n) && (y>=0 && y<n) && (v[x][y]==0) && (m[x][y]==1)){
    return true;
  }
  return false;
}
void solve(vector<vector<int>>& m ,int n,int x,int y,vector<vector<int>> v,string path,
vector<string>& ans){
  if(x==n-1 && y==n-1){
    ans.push_back(path);
    return ;
    
  }
  v[x][y]=1;
  
  // down
  int newx=x+1;
  int newy =y;
  
  if(isSafe(m,n,newx,newy,v)){
    path.push_back('D');
    solve(m,n,newx,newy,v,path,ans);
    path.pop_back();
  }
  newx=x;
  newy=y+1;
  if(isSafe(m,n,newx,newy,v)){
    path.push_back('R');
    solve(m,n,newx,newy,v,path,ans);
    path.pop_back();
  }
  newx=x;
  newy=y-1;
  if(isSafe(m,n,newx,newy,v)){
    path.push_back('L');
    solve(m,n,newx,newy,v,path,ans);
    path.pop_back();
  }
  newx=x-1;
  newy=y;
  if(isSafe(m,n,newx,newy,v)){
    path.push_back('U');
    solve(m,n,newx,newy,v,path,ans);
    path.pop_back();
  }
  v[x][y]=0;
  
}
vector<string> ratMaze(vector<vector<int>>& m ,int n){
  vector<string> ans;
  if(m[0][0]==0){
    return ans;
    }
  string path = "";
  int srx= 0;
  int sry =0;
  vector<vector<int>> v =m;
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
      v[i][j]=0;
    }
  }
  solve(m,n,srx,sry,v,path,ans);
  sort(ans.begin(),ans.end());
  return ans;
}

int main() {
  int n =4;
    vector<vector<int>> arr = {{1,1,1,1},
                              {0,0,1,1},
                              {1,1,0,1},
                              {0,0,0,1}};
    vector<string> ans = ratMaze(arr,n);
    for(int i=0;i<ans.size();i++){
      cout<<ans[i]<<"  ";
    }
    
    return 0;
}

C++ Online Compiler

Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!

Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}