diff --git a/lab_3/21/Makefile b/lab_3/21/Makefile
new file mode 100644
index 0000000..2c0c131
--- /dev/null
+++ b/lab_3/21/Makefile
@@ -0,0 +1,21 @@
+binary = queens
+folder = queens
+objects = $(patsubst %.cpp,%.o,$(wildcard *.cpp))
+
+run: $(binary)
+	./$(binary)
+
+$(binary): $(objects)
+	g++ -g3 -o $@ $^
+
+%.o: %.cpp
+	g++ -g3 -c -o $@ $<
+
+clean:
+	rm -f *.o
+
+clear: clean
+	rm -f *.zip $(binary)
+
+zip: clean
+	zip $(folder) Makefile *.cpp *.h
diff --git a/lab_3/21/queens.cpp b/lab_3/21/queens.cpp
new file mode 100644
index 0000000..f577398
--- /dev/null
+++ b/lab_3/21/queens.cpp
@@ -0,0 +1,65 @@
+#include "queens.hh"
+#include <cstdlib>
+#include <iostream>
+#include <vector>
+#include <random>
+
+using namespace queens;
+
+Configuration::Configuration(int m, int n, int number_of_pieces) {
+    this->number_of_pieces = number_of_pieces;
+    this->board = new Board;
+
+    this->board->m = m; //x direction
+    this->board->n = n; //y direction
+
+    //get a random number generator:
+    //the random device that will seed the generator
+    std::random_device seeder;
+    //then make a mersenne twister engine
+    std::mt19937 engine(seeder());
+    //then the easy part... the distribution
+    std::uniform_int_distribution<int> m_rand(1, m);
+    std::uniform_int_distribution<int> n_rand(1, n);
+
+    for (int i=0; i<number_of_pieces; i++)
+    {
+        this->pieces.push_back(Queen(m_rand(engine), n_rand(engine)));
+    }
+}
+
+std::vector<Conflict> Configuration::get_conflicts()
+{
+    std::vector<Conflict> conflicts;
+    for (int i = 0; i<this->number_of_pieces; i++)
+    {
+
+        // The piece we will check against the others:
+        Piece* piece = &this->pieces[i];
+        // For every new i we need to check one fewer i
+        for (int j = i+1; j<number_of_pieces; j++)
+        {
+            Piece* enemy_piece = &this->pieces[j];
+            if (piece->x == enemy_piece->x or
+                piece->y == enemy_piece->y or
+                piece->x - enemy_piece->x == piece->y - enemy_piece->x)
+            {
+                Conflict conflict;
+                conflict.piece_1 = i;
+                conflict.piece_1_x = piece->x;
+                conflict.piece_1_y = piece->y;
+                conflict.piece_2 = j;
+                conflict.piece_2_x = enemy_piece->x;
+                conflict.piece_2_y = enemy_piece->y;
+                conflicts.push_back(conflict);
+            }
+        }
+    }
+    return conflicts;
+}
+
+Piece::Piece(int x, int y)
+{
+    this->x = x;
+    this->y = y;
+}
\ No newline at end of file
diff --git a/lab_3/21/queens.hh b/lab_3/21/queens.hh
new file mode 100644
index 0000000..8af8c96
--- /dev/null
+++ b/lab_3/21/queens.hh
@@ -0,0 +1,48 @@
+#include <array>
+#include <vector>
+
+namespace queens
+{   
+    // Easy way represent a conflict:
+    struct Conflict 
+    {
+        int piece_1;
+        int piece_1_x;
+        int piece_1_y;
+        int piece_2;
+        int piece_2_x;
+        int piece_2_y;
+    };
+    class Piece
+    {
+        public:
+            int x;
+            int y;
+
+            Piece(int x, int y);
+    };
+    class Queen: public Piece
+    {
+        using Piece::Piece;
+    };
+
+    class Board
+    {
+        public:
+            int m;
+            int n;
+    };
+
+    class Configuration
+    {
+        public:
+            int number_of_pieces;
+            std::vector<Piece> pieces;
+            Board* board;
+
+            Configuration(int m, int n, int number_of_pieces);
+            std::vector<Conflict> get_conflicts();
+    };
+
+
+}
\ No newline at end of file
diff --git a/lab_3/21/test.cpp b/lab_3/21/test.cpp
new file mode 100644
index 0000000..54c082c
--- /dev/null
+++ b/lab_3/21/test.cpp
@@ -0,0 +1,21 @@
+#include "queens.hh"
+#include <iostream>
+
+void print_conflict(queens::Conflict c)
+{
+    std::cout << "🚨 Conflict! "<< "Piece 1: x="<< c.piece_1_x << ", y=" << c.piece_1_y
+                << " Piece 2: x="<< c.piece_2_x << ", y=" << c.piece_2_y << "\n";
+}
+
+int main()
+{
+    queens::Configuration config = queens::Configuration(8, 8, 10);
+    std::vector<queens::Conflict> conflicts = config.get_conflicts();
+    for (int i=0; i<conflicts.size(); i++)
+    {
+        print_conflict(conflicts[i]);
+
+    }
+
+
+}
\ No newline at end of file