DataStructure/10_mergesort.cpp at master · rohangoyal755/DataStructure · GitHub

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#include<iostream>
using namespace std;
void selectionSort(int a[], int n)
{
   int i, j, min_idx,temp;
   for (i = 0; i < n-1; i++)
    {
        min_idx = i;
        for (j = i+1; j < n; j++)
		{
          if (a[j] < a[min_idx])
          {
            min_idx = j;
            temp=a[min_idx];
            a[min_idx]=a[i];
            a[i]=temp;
           }
       }
    }
   for(int i=0;i<n;i++)
   {
   	cout<<a[i]<<" ";
   }
}

void printArray(int a[], int n)
{
   int i;
   for (i=0; i < n; i++)
       cout<< a[i]<<" ";
   cout<<endl;
}

void Merge(int arr[], int l, int m, int r)
{
    int i, j, k;
    int n1 = m - l + 1;
    int n2 =  r - m;
    int L[n1], R[n2];
    for (i = 0; i < n1; i++)
        L[i] = arr[l + i];
    for (j = 0; j < n2; j++)
        R[j] = arr[m + 1+ j];
    i = 0;
    j = 0;
    k = l;
    while (i < n1 && j < n2)
    {
        if (L[i] <= R[j])
        {
            arr[k] = L[i];
            i++;
        }
        else
        {
            arr[k] = R[j];
            j++;
        }
        k++;
    }
    while (i < n1)
    {
        arr[k] = L[i];
        i++;
        k++;
    }
    while (j < n2)
    {
        arr[k] = R[j];
        j++;
        k++;
    }
}
void mergeSort(int arr[], int l, int r)
{
    if (l < r)
    {

        int m = l+(r-l)/2;

        mergeSort(arr, l, m);
        mergeSort(arr, m+1, r);
        Merge(arr, l, m, r);
    }
}
void printarray(int A[], int n)
{
    int i;
    for (i=0; i < n; i++)
        cout<<A[i]<<"\t";
    cout<<endl;
}

int main()
{
 int n;
 int a[100];
 cout<<"enter length of array"<<endl;
 cin>>n;
 cout<<"enter the array"<<endl;
 for(int i=0;i<n;i++)
 {
     cin>>a[i];
 }
 cout<<"sorted array:"<<endl;
    selectionSort(a, n);
      cout<<"enter length of second array"<<endl;
      int m;
 cin>>m;
 int arr[m+n];
 cout<<"enter the array"<<endl;
 for(int i=n;i<m+n;i++)
 {
     cin>>arr[i];
 }
 for(int i=0;i<n;i++)
 {
     arr[i]=a[i];
 }
mergeSort(arr,0,n+m - 1);
printarray(arr, n+m);
    return 0;
}