Neerajpathak07 patch 1

Hashmapping.C++

@@ -0,0 +1,46 @@
+#include <iostream>
+#include <map>
+#include <unordered_map>
+using namespace std;
+
+int main(int argc, char const *argv[])
+{
+    //creation of map
+    map<string,int>m;
+
+    //insertion
+    //1
+    pair<string,int> p= make_pair("Neeraj",7);
+    m.insert(p);
+
+    //2
+    pair<string,int> pair2("love",2);
+    m.insert(pair2);
+
+    //3
+    m["Neeraj"]=1;
+
+    //search
+    cout <<m["Neeraj"] <<endl;
+    cout <<m.at("love") <<endl;
+
+    //to cheack presence
+    cout <<m.count("love") <<endl;
+
+    //erase
+    m.erase("love"); 
+    cout<<m.size() << endl;
+
+    for(auto i:m){
+        cout<<i.first << " " << i.second << endl;
+    }
+
+    //itereator
+    map<string,int> :: iterator it = m.begin();
+
+    while(it!=m.end()){
+        cout << it->first <<" " << it->second <<endl;
+
+    }
+    return 0;
+}

MergeSort.c

@@ -0,0 +1,84 @@
+#include <iostream>
+using namespace std;
+
+
+void merge(int *arr,int s,int e){
+    int len1= mid-s+1;
+    int len2= e-mid;
+
+    int *first=new int(len1);
+    int *second=new int(len2);
+
+//copy values into new array
+    int mainArrayIndex=s;
+    for (int i = 0; i < len1; i++)
+    {
+        first[i]=arr[k++];
+    }
+
+    int mainArrayIndex = mid+1;
+    for (int i = 0; i < len2; i++)
+    {
+        second[i]=arr[k++];
+
+    }
+    //merge both the sorted arrays into final array
+    int index1=0;
+    int index2=0;
+     mainArrayIndex=0;
+
+    while(index1 < len1 && index2 < len2){
+        if(first(index1) < second(index2)){
+            arr[mainArrayIndex++]=frist[index1++];
+        }
+        else
+        {
+            arr[mainArrayIndex++]=second[index2++];
+
+        }
+
+    }
+    //adding the remaining elements of the first array into the final output array
+
+    while (index1 < len1){
+        arr[mainArrayIndex++]=first[index1++];
+
+    }
+   //adding the remaining elements of the second array into the final output array
+
+    while (index2<len2)
+    {
+        arr[mainArrayIndex++]= second[index2++];
+    }
+
+
+
+}
+
+void mergeSort(int *arr,int s,int e){
+    //base case
+    if(s>e)
+    return ;
+    int mid=(s+e)/2;
+
+
+    //sort left part
+    mergeSort(arr,s,mid);
+
+    //right part sorting
+    mergeSort(arr,mid+1,e);
+
+    //merge the two sub-divided arrays
+    merge(arr,s,e);
+
+
+}
+
+int main(int argc, char const *argv[])
+{
+    int arr[5]={1,24,2,35,23};
+    int n=5;
+
+    mergeSort(arr,0,n-1);
+    return 0;
+}