diff --git a/binary-search-for-the-answer/Program.cs b/binary-search-for-the-answer/Program.cs
new file mode 100644
index 0000000..1a1ab7d
--- /dev/null
+++ b/binary-search-for-the-answer/Program.cs
@@ -0,0 +1,57 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Collections.Generic;
+
+namespace ConsoleApplication2
+{
+    internal class Program
+    {
+        private static List<int> arr = new List<int>();
+        private static int N, k;
+
+        private static bool Check(int x)
+        {
+            int _k = 1;
+            int last_cow = arr[0];
+            
+            foreach (var c in arr) 
+            {
+                if (c - last_cow >= x) 
+                {
+                    _k++;
+                    last_cow = c;
+                }
+            }
+            
+            return _k >= k;
+        }
+
+        public static void Main(string[] args)
+        {
+            StreamReader reader = new StreamReader("C:/Users/polin/RiderProjects/ConsoleApplication2/ConsoleApplication2/5.in");
+            StreamWriter writer = new StreamWriter("C:/Users/polin/RiderProjects/ConsoleApplication2/ConsoleApplication2/test.out");
+
+            N = int.Parse(reader.ReadLine());
+            k = int.Parse(reader.ReadLine()) + 1;
+
+            while (!reader.EndOfStream)
+                arr.Add(int.Parse(reader.ReadLine()));
+            
+            int left = 0;
+            int right = arr[N-1] - arr[0] + 1;
+            
+            while (right - left > 1) 
+            {
+                int middle = (left + right) / 2;
+                if (Check(middle)) left = middle;
+                else right = middle;
+            }
+            
+            writer.WriteLine(left);
+
+            reader.Close();
+            writer.Close();
+        }
+    }
+}
\ No newline at end of file
diff --git a/binary-search/Program.cs b/binary-search/Program.cs
new file mode 100644
index 0000000..75239e7
--- /dev/null
+++ b/binary-search/Program.cs
@@ -0,0 +1,48 @@
+using System;
+using System.IO;
+using System.Linq;
+
+namespace ConsoleApplication1
+{
+    internal class Program
+    {
+        private static int[] arr;
+
+        public static void Main(string[] args)
+        {
+            StreamReader reader = new StreamReader("C:/Users/polin/RiderProjects/ConsoleApplication1/5.in");
+            StreamWriter writer = new StreamWriter("C:/Users/polin/RiderProjects/ConsoleApplication1/test.out");
+
+            int N = int.Parse(reader.ReadLine());
+            arr = reader.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
+            int K = int.Parse(reader.ReadLine());
+
+            int left = 0;
+            int right = N - 1;
+
+            while (!reader.EndOfStream)
+                writer.WriteLine(Search(left, right, int.Parse(reader.ReadLine())));
+                //Console.WriteLine(Search(left, right, int.Parse(reader.ReadLine())));
+
+            reader.Close();
+            writer.Close();
+        }
+
+        private static int Search(int left, int right, int searchElem)
+        {
+            int middle = (left + right) / 2;
+            if (searchElem == arr[middle]) return middle;
+
+            if (Math.Abs(right - left) <= 1)
+            {
+                if (arr[right] == searchElem) return right;
+                if (arr[left] == searchElem) return left; 
+                else return -1;
+            }
+
+            if (searchElem > arr[middle]) return Search(middle, right, searchElem);
+            if (searchElem < arr[middle]) return Search(left, middle, searchElem);
+            else return -1;
+        }
+    }
+}
\ No newline at end of file
diff --git a/priority-queue/Program.cs b/priority-queue/Program.cs
new file mode 100644
index 0000000..8339421
--- /dev/null
+++ b/priority-queue/Program.cs
@@ -0,0 +1,85 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Collections.Generic;
+
+namespace ConsoleApplication3
+{
+    internal class Program
+    {
+        private static List<int> heap = new List<int>();
+        private static int N;
+        private static StreamWriter writer;
+        
+        public static void Swap(int index1, int index2)
+        {
+            int temp = heap[index1];
+            heap[index1] = heap[index2];
+            heap[index2] = temp;
+        }
+
+        public static void SiftDown(int i)
+        {
+            while (2 * i + 1 < heap.Count)
+            {
+                int left = 2 * i + 1;
+                int right = 2 * i + 2;
+                int j = left;
+
+                if ((right < heap.Count) && (heap[right] > heap[left]))
+                    j = right;
+                
+                if (heap[i] >= heap[j])
+                    break;
+                
+                Swap(i, j);
+                i = j;
+            }
+        }
+
+        public static void SiftUp(int i)
+        {
+            while (heap[i] > heap[(i - 1) / 2])
+            {
+                Swap(i, (i - 1) / 2);
+                i = (i - 1) / 2;
+            }
+        }
+
+        public static void Insert(int key)
+        {
+            heap.Add(key);
+            SiftUp(heap.Count - 1);
+        }
+
+        public static void ExtractMax()
+        {
+            writer.WriteLine(heap[0]);
+            
+            heap[0] = heap[heap.Count - 1];
+            heap.RemoveAt(heap.Count - 1);
+            SiftDown(0);
+        }
+
+        public static void Main(string[] args)
+        {
+            StreamReader reader = new StreamReader("C:/Users/polin/RiderProjects/ConsoleApplication3/ConsoleApplication3/3.in");
+            writer = new StreamWriter("C:/Users/polin/RiderProjects/ConsoleApplication3/ConsoleApplication3/result.out");
+            
+            N = int.Parse(reader.ReadLine());
+
+            while (!reader.EndOfStream)
+            {
+                string elem = reader.ReadLine();
+                
+                if (elem=="GET")
+                    ExtractMax();
+                else
+                    Insert(int.Parse(elem));
+            }
+
+            reader.Close();
+            writer.Close();
+        }
+    }
+}
\ No newline at end of file