Merge sort added successfully

C++/merge-sort.cpp

@@ -0,0 +1,84 @@
+#include <iostream>
+#include <vector>
+
+void merge(std::vector<int>& arr, int left, int middle, int right) {
+    int n1 = middle - left + 1;
+    int n2 = right - middle;
+
+    // Create temporary arrays
+    std::vector<int> left_arr(n1);
+    std::vector<int> right_arr(n2);
+
+    // Copy data to temporary arrays left_arr[] and right_arr[]
+    for (int i = 0; i < n1; i++) {
+        left_arr[i] = arr[left + i];
+    }
+    for (int i = 0; i < n2; i++) {
+        right_arr[i] = arr[middle + 1 + i];
+    }
+
+    // Merge the two sorted arrays back into arr[]
+    int i = 0; 
+    int j = 0;
+    int k = left; 
+
+    while (i < n1 && j < n2) {
+        if (left_arr[i] <= right_arr[j]) {
+            arr[k] = left_arr[i];
+            i++;
+        } else {
+            arr[k] = right_arr[j];
+            j++;
+        }
+        k++;
+    }
+
+    // Copy the remaining elements of left_arr[], if any
+    while (i < n1) {
+        arr[k] = left_arr[i];
+        i++;
+        k++;
+    }
+
+    // Copy the remaining elements of right_arr[], if any
+    while (j < n2) {
+        arr[k] = right_arr[j];
+        j++;
+        k++;
+    }
+}
+
+void merge_sort(std::vector<int>& arr, int left, int right) {
+    if (left < right) {
+        int middle = left + (right - left) / 2;
+
+        // Sort first and second halves
+        merge_sort(arr, left, middle);
+        merge_sort(arr, middle + 1, right);
+
+        // Merge the sorted halves
+        merge(arr, left, middle, right);
+    }
+}
+
+int main() {
+    int n;
+    std::cout << "Enter the number of elements: ";
+    std::cin >> n;
+
+    std::vector<int> input_list(n);
+    std::cout << "Enter " << n << " elements:\n";
+    for (int i = 0; i < n; i++) {
+        std::cin >> input_list[i];
+    }
+
+    merge_sort(input_list, 0, n - 1);
+
+    std::cout << "Sorted list: ";
+    for (int i = 0; i < n; i++) {
+        std::cout << input_list[i] << " ";
+    }
+    std::cout << std::endl;
+
+    return 0;
+}

C++/quick-sort.cpp

@@ -0,0 +1,59 @@
+#include <iostream>
+#include <vector>
+
+void quick_sort(std::vector<int>& arr, int left, int right) {
+    if (left < right) {
+        int pivot = arr[left];  // Choose a pivot element (first element in this case)
+        int i = left;
+        int j = right;
+
+        while (i < j) {
+            while (i < j && arr[j] >= pivot) {
+                j--;
+            }
+            if (i < j) {
+                arr[i] = arr[j];
+                i++;
+            }
+
+            while (i < j && arr[i] <= pivot) {
+                i++;
+            }
+            if (i < j) {
+                arr[j] = arr[i];
+                j--;
+            }
+        }
+
+        arr[i] = pivot;
+
+        // Recursively sort the left and right sub-arrays
+        quick_sort(arr, left, i - 1);
+        quick_sort(arr, i + 1, right);
+    }
+}
+
+int main() {
+    std::vector<int> input_list;
+    int n;
+
+    std::cout << "Enter the number of elements: ";
+    std::cin >> n;
+
+    std::cout << "Enter " << n << " elements:\n";
+    for (int i = 0; i < n; i++) {
+        int element;
+        std::cin >> element;
+        input_list.push_back(element);
+    }
+
+    quick_sort(input_list, 0, n - 1);
+
+    std::cout << "Sorted list: ";
+    for (int i = 0; i < n; i++) {
+        std::cout << input_list[i] << " ";
+    }
+    std::cout << std::endl;
+
+    return 0;
+}

C++/sieve algorithm.cpp

@@ -0,0 +1,32 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define ll long long
+const int N = 1e7 + 10;
+vector<bool> isprime(N,1);
+
+
+int main(){
+
+    isprime[0]=false;isprime[1]=false;
+    for(int i=2; i<N; i++){
+        if(isprime[i]==true){
+            for(int j = 2*i; j<N; j+=i){
+                isprime[j]= false;
+            }
+        }
+    }
+
+
+    // Input the number to check whether prime or not
+
+    ll x;
+    cin>>x;
+
+    if(!isprime[x]){
+        cout<<x<<" is not prime number"<<endl;
+    }else{
+         cout<<x<<" is prime number"<<endl;
+    }
+
+  return 0;
+}