#include <bits/stdc++.h>
using namespace std;


bool is_safe(vector<vector<int>> board,int row,int column,int n)
{
  for(int i=0;i<row;i++) {
    if(board[i][column]==1)
      return false;
  }
  for(int i=row, j=column;i>=0 && j>=0;i--,j--) {
    if(board[i][j]==1)
      return false;
  }
  for(int i=row, j=column;i>=0 && j<n;i--,j++) {
    if(board[i][j]==1)
      return false;
  }
  
  return true;
}

void printQueen(vector<vector<int>> board)
{
  for(int i=0;i<board.size();i++) {
    
    for(int j=0;j<board.size();j++) {
      
      cout<<board[i][j]<<" ";
    }
  }
  cout<<endl;
}


void nqueen(vector<vector<int>> board,int i,int n)
{
  if(i==n) {
    printQueen(board);
    return;
  }
  
  for(int j=0;j<n;j++) {
    if(is_safe(board,i,j,n))
    {
      board[i][j]=1;
      nqueen(board,i+1,n);
      
    }
    board[i][j]=0;
  }
}

int main() 
{
    int n;
    cin>>n;
    vector<vector<int>> board(n, vector<int>(n, 0));
    
    nqueen(board,0,n);
    
    return 0;
}
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C++ Online Compiler

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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
}