Hacktoberfest-2022

Sorting Algorithms/Bubble Sort/bubble_sort.cpp

@@ -0,0 +1,35 @@
+//Repeatedly swap two adjacent elements if they are in wrong order.
+// For n elements of an array, it takes (n-1) iterations to complete. So, for i^th iteration, it will be (n-i).
+#include<iostream>
+using namespace std;
+int main()
+{
+    int n;
+    cout<<"Enter the number of elements in an array: ";
+    cin>>n;
+    int array[n];
+    cout<<"Enter the elements of the array:"<<endl;
+    for(int i=0;i<n;i++)
+    {
+        cin>>array[i];
+    }
+    int counter=1;
+    while(counter<n-1)
+    {
+        for(int i=0;i<n-1;i++)
+        {
+            if(array[i]>array[i+1])
+            {
+                int temp= array[i];
+                array[i]=array[i+1];
+                array[i+1]=temp;
+            }
+        }
+        counter++;
+    }
+    for(int i=0;i<n;i++)
+    {
+        cout<<array[i]<<" ";
+    }
+    return 0;
+}

Sorting Algorithms/Insertion Sort/insertion_sort.cpp

@@ -0,0 +1,35 @@
+//Insert an element from unsorted array to its correct position in the sorted array.
+#include<iostream>
+using namespace std;
+int main()
+{
+    int n;
+    // cout<<"Enter the number of elements of array: ";
+    cin>>n;
+    int array[n];
+    // cout<<"Enter the elements of the array:"<<endl;
+    for(int i=0;i<n;i++)
+    {
+        cin>>array[i];
+    }
+    int count=0;
+    for(int i=1;i<n;i++)
+    {
+        // count=0;
+        int j=i-1;
+        int current=array[i];
+        while(array[j]>current && j>=0)
+        {
+            array[j+1]=array[j];
+            j--;
+            count++;
+        }
+       array[j+1]=current;
+    }
+    // for(int i=0;i<n;i++)
+    // {
+    //     cout<<array[i]<<" ";
+    // }
+    cout<<count;
+        return 0;
+}

Sorting Algorithms/Merge Sort/merge.cpp

@@ -0,0 +1,86 @@
+#include<iostream>
+using namespace std;
+void merge(int array[],int l,int mid,int r)
+{
+    int n1=mid+1-l;
+    int n2=r-mid;
+
+    int a[n1];
+    int b[n2]; 
+    // temporary arrays.
+
+    for(int i=0;i<n1;i++)
+    {
+        a[i]=array[l+i];
+    }
+    for(int i=0;i<n2;i++)
+    {
+        b[i]=array[mid+1+i];
+    }
+
+    int i=0;int j=0; int k=l;
+    while(i<n1 and j<n2)
+    {
+        if(a[i]<b[j])
+        {
+            array[k]=a[i];
+            i++;
+            k++;
+        }
+        else
+        {
+            array[k]=b[j];
+            j++;
+            k++;
+        }
+    }
+    while(i<n1)
+    {
+        array[k]=a[i];
+        i++;
+        k++;
+    }
+    while(j<n2)
+    {
+        array[k]=b[j];
+        k++;
+        j++;
+    }
+}
+void mergesort(int array[],int l,int r)
+{
+    if(l<r)
+    {
+        int mid=(l+r)/2;
+        mergesort(array,l,mid);
+        mergesort(array,mid+1,r);
+
+        merge(array,l,mid,r);
+    }
+}
+int main()
+{
+    int n;
+    cout<<"Enter the size of array: ";
+    cin>>n;
+    int array[n];
+    cout<<"Enter the elements of array: ";
+    for(int i=0;i<n;i++)
+    {
+        cin>>array[i];
+    }
+    for(int i=0;i<n;i++)
+    {
+        cout<<array[i]<<" ";
+    }
+    cout<<endl<<endl;
+    mergesort(array,0,n-1);
+    cout<<"The sorted array is: ";
+    for(int i=0;i<n;i++)
+    {
+        cout<<array[i]<<" ";
+    }
+    cout<<endl;
+
+    return 0;
+}

Sorting Algorithms/Selection Sort/selection_sorting.cpp

@@ -0,0 +1,30 @@
+//Repeatedly swap two elements if they are in wrong order.
+#include<iostream>
+using namespace std;
+int main()
+{
+    int n;
+    cin>>n;
+    int array[n];
+    for(int i=0;i<n;i++)
+    {
+        cin>>array[i];
+    }
+    for(int i=0;i<n-1;i++)
+    {
+        for(int j=i+1;j<n;j++)
+        {
+            if(array[i]>array[j])
+            {
+                int temp=array[j];
+                array[j]=array[i];
+                array[i]=temp;
+            }
+        }
+    }
+    for(int i=0;i<n;i++)
+    {
+        cout<<array[i]<<" ";
+    }
+    return 0;
+}