Algorithms

Author: harshit2608

ALGORITHMS/Searching/BinarySearch.cpp

@@ -0,0 +1,31 @@
+#include <bits/stdc++.h>
+
+int binarysearch(int arr[], int n, int target)
+{
+    int low = 0, high = n;
+    while (low <= high)
+    {
+        int mid = (low + high) / 2;
+        if (arr[mid] == target)
+        {
+            return mid;
+        }
+        else if (arr[mid] > target)
+        {
+            high = mid - 1;
+        }
+        else
+        {
+            low = mid + 1;
+        }
+    }
+    return -1;
+}
+
+int main()
+{
+    int target = 5, n = 10;
+    int arr[n] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+    std::cout << binarysearch(arr, n, target);
+    return 0;
+}

ALGORITHMS/Searching/LinearSearch.cpp

@@ -0,0 +1,21 @@
+#include <bits/stdc++.h>
+
+int linearsearch(int arr[], int n, int target)
+{
+    for (int i = 0; i < n; ++i)
+    {
+        if (arr[i] == target)
+        {
+            return i;
+        }
+    }
+    return -1;
+}
+
+int main()
+{
+    int n = 10, target = 23;
+    int arr[n] = {23, 15, 89, 17, 56, 852, 753, 96521, 546, 0};
+    std::cout << linearsearch(arr, n, target);
+    return 0;
+}

ALGORITHMS/Sorting/BubbleSort.cpp

@@ -0,0 +1,52 @@
+#include <bits/stdc++.h>
+
+void bubblesort(std::vector<int> &arr)
+{
+    int n = arr.size();
+    bool swapped = false;
+    for (int i = 0; i < n; ++i)
+    {
+        swapped = false;
+        for (int j = 0; j < n - i - 1; ++j)
+        {
+            if (arr[j] > arr[j + 1])
+            {
+                std::swap(arr[j], arr[j + 1]);
+                swapped = true;
+            }
+        }
+        if (swapped = false)
+        {
+            break;
+        }
+    }
+}
+
+void printArray(std::vector<int> arr)
+{
+    for (int i = 0; i < arr.size(); ++i)
+    {
+        std::cout << arr[i] << " ";
+    }
+    std::cout << "\n";
+}
+
+int main()
+{
+    int t;
+    std::cin >> t;
+    while (t--)
+    {
+        int n, ele;
+        std::cin >> n;
+        std::vector<int> arr(n, 0);
+        for (int i = 0; i < n; ++i)
+        {
+            std::cin >> ele;
+            arr[i] = ele;
+        }
+        bubblesort(arr);
+        printArray(arr);
+    }
+    return 0;
+}

ALGORITHMS/Sorting/Dutch National Flag(DNF).bin

@@ -0,0 +1,63 @@
+#include <bits/stdc++.h>
+
+//INPUT:
+// 2
+// 5
+// 1 1 2 2 0
+// 0 1 2
+// 10
+// 9 9 5 5 6 5 9 5 6 9
+// 5 6 9
+
+void DNF(std::vector<int> &arr, int f, int s, int t)
+{
+    int low = 0, mid = 0, high = arr.size() - 1;
+    while (mid <= high)
+    {
+        if (arr[mid] == f)
+        {
+            std::swap(arr[mid], arr[low]);
+            low++;
+            mid++;
+        }
+        else if (arr[mid] == s)
+        {
+            mid++;
+        }
+        else
+        {
+            std::swap(arr[mid], arr[high]);
+            high--;
+        }
+    }
+}
+
+void printArray(std::vector<int> arr)
+{
+    for (int i = 0; i < arr.size(); ++i)
+    {
+        std::cout << arr[i] << " ";
+    }
+    std::cout << "\n";
+}
+
+int main()
+{
+    int t;
+    std::cin >> t;
+    while (t--)
+    {
+        int n, ele, f, s, th;
+        std::cin >> n;
+        std::vector<int> arr(n, 0);
+        for (int i = 0; i < n; ++i)
+        {
+            std::cin >> ele;
+            arr[i] = ele;
+        }
+        std::cin >> f >> s >> th;
+        DNF(arr, f, s, th);
+        printArray(arr);
+    }
+    return 0;
+}

ALGORITHMS/Sorting/Dutch National Flag(DNF).cpp

@@ -0,0 +1,44 @@
+#include <bits/stdc++.h>
+
+void insertionsort(std::vector<int> &arr)
+{
+    for (int i = 1; i < arr.size(); ++i)
+    {
+        int key = arr[i], j = i - 1;
+        while (j >= 0 && arr[j] > key)
+        {
+            arr[j + 1] = arr[j];
+            j = j - 1;
+        }
+        arr[j + 1] = key;
+    }
+}
+
+void printArray(std::vector<int> arr)
+{
+    for (int i = 0; i < arr.size(); ++i)
+    {
+        std::cout << arr[i] << " ";
+    }
+    std::cout << "\n";
+}
+
+int main()
+{
+    int t;
+    std::cin >> t;
+    while (t--)
+    {
+        int n, ele;
+        std::cin >> n;
+        std::vector<int> arr(n, 0);
+        for (int i = 0; i < n; ++i)
+        {
+            std::cin >> ele;
+            arr[i] = ele;
+        }
+        insertionsort(arr);
+        printArray(arr);
+    }
+    return 0;
+}

ALGORITHMS/Sorting/InsertionSort.cpp

@@ -0,0 +1,47 @@
+#include <bits/stdc++.h>
+
+void selectionsort(std::vector<int> &arr)
+{
+    int min = 0;
+    for (int i = 0; i < arr.size() - 1; ++i)
+    {
+        min = i;
+        for (int j = i + 1; j < arr.size(); ++j)
+        {
+            if (arr[min] > arr[j])
+            {
+                min = j;
+            }
+        }
+        std::swap(arr[min], arr[i]);
+    }
+}
+
+void printArray(std::vector<int> arr)
+{
+    for (int i = 0; i < arr.size(); ++i)
+    {
+        std::cout << arr[i] << " ";
+    }
+    std::cout << "\n";
+}
+
+int main()
+{
+    int t;
+    std::cin >> t;
+    while (t--)
+    {
+        int n, ele;
+        std::cin >> n;
+        std::vector<int> arr(n, 0);
+        for (int i = 0; i < n; ++i)
+        {
+            std::cin >> ele;
+            arr[i] = ele;
+        }
+        selectionsort(arr);
+        printArray(arr);
+    }
+    return 0;
+}

ALGORITHMS/Sorting/SelectionSort.cpp

@@ -20,3 +20,7 @@ And if the problem you want to serach is form codechef you have to enter the pro
 - [Hackerrank](https://www.hackerrank.com/dashboard)
 - [InterViewBit](https://www.interviewbit.com/practice/)
 - [Leet Code](https://leetcode.com/problemset/all/)
+
+## ALGORITHMS
+
+Algorithms folder contain various algorithms in c++