Merge_Sort

merge_sort.cpp

@@ -0,0 +1,93 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+
+void merge(int arr[],int left,int mid,int right)
+{
+    //number of elements in the divided arrays
+    int nL=mid-left+1;  //nL number of elements in left array
+    int nR = right-mid; //nR number of elements in right array
+
+    int L[nL],R[nR]; //temporary arrays
+
+    for(int i=0;i<nL;i++)
+    {
+        L[i] = arr[left+i]; 
+    }
+    for(int j=0;j<nR;j++)
+    {
+        R[j]=arr[mid+1+j];
+    }
+
+    int i=0,j=0,k=left;
+
+    while(i<nL && j<nR)
+    {
+        if(L[i]<=R[j])
+        {
+            arr[k] = L[i];
+            i++;
+        }
+        else{
+            arr[k]=R[j];
+            j++;
+        }
+        k++;
+    }
+
+    //copying the remaining elements
+    while(i<nL)
+    {
+        arr[k]=L[i];
+        i++;
+        k++;
+    }
+
+    while(i<nR)
+    {
+        arr[k]=R[j];
+        j++;
+        k++;
+    }
+}
+
+void mergeSort(int arr[],int left,int right)
+{
+    if(left<right)
+    {
+        int mid = left + (right-left)/2;
+        mergeSort(arr,left,mid);
+        mergeSort(arr,mid+1,right);
+
+        //merging the sorted arrays
+        merge(arr,left,mid,right);
+    }
+}
+//printting the array
+void printArray(int arr[],int n)
+{
+    for(int i=0;i<n;i++)
+    {
+        cout<<arr[i]<<" ";
+    }
+    cout<<endl;
+}
+
+int main()
+{
+    int n;
+    cout<<"Enter the size of array :";
+    cin>>n;
+    int arr[n];
+    cout<<"Enter the elements: ";
+    for(int i=0;i<n;i++)
+    {
+        cin>>arr[i];
+    }
+
+    mergeSort(arr,0,n-1);
+
+    cout<<"The sorted Array is: "<<endl;
+    printArray(arr,n);
+    return 0;
+}

priority_queue.cpp

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+
+//by default priority queue creates max-heap.
+
+#include <bits/stdc++.h>
+using namespace std;
+
+
+
+void showpq(priority_queue<int>pq)
+{
+    priority_queue<int>p = pq; //just copied it
+    while(!p.empty())
+    {
+        cout<<"\t"<<p.top();
+        p.pop();
+    }
+    cout<<"\n";
+}
+
+
+int main()
+{
+    priority_queue<int>pq; 
+
+    // we can create a min heap priority queue using the below line
+    //priority_queue<int,vector<int>,greater<int>>pq;
+    pq.push(20);
+    pq.push(40);
+    pq.push(30);
+    pq.push(3);
+    pq.push(1);
+
+    cout<<"The priority Queue is: ";
+    showpq(pq);
+
+
+
+return 0;
+}
+
+
+
+
+
+
+
+