Create merge_sort.cpp

Author: Shivani-Bahuguna

merge_sort.cpp

@@ -0,0 +1,52 @@
+#include<bits/stdc++.h>
+
+using namespace std;
+
+
+void merge(vector<int> &arr, int l, int m, int r) {
+	
+	int nl = m-l+1; 
+	int nr = r-m;
+	vector<int> larr(nl);
+	vector<int> rarr(nr);
+	for(int i=0; i<nl; i++) larr[i] = arr[l+i];
+	for(int j=0; j<nr; j++) rarr[j] = arr[m+1+j];
+	int i=0, j=0, k=l;
+	while(i < nl && j < nr) {
+		if(larr[i] <= rarr[j]) {
+         	arr[k] = larr[i];
+         	i++;
+      	}else{
+         	arr[k] = rarr[j];
+         	j++;
+      	}
+      	k++;
+	}
+   	while(i<nl) {       
+      	arr[k] = larr[i];
+      	i++; k++;
+   	}
+   	while(j<nr) {     
+      	arr[k] = rarr[j];
+      	j++; k++;
+   	}
+}
+
+void mergeSort(vector<int> &arr, int l, int r) {
+	int m;
+	if(l < r) {
+		int m = l+(r-l)/2;
+		mergeSort(arr, l, m);
+		mergeSort(arr, m+1, r);
+		merge(arr, l, m, r);
+	}
+}
+
+int main() {
+	vector<int> arr = {-10, 9, 0, 3, 4, -7};
+	mergeSort(arr, 0, 5);
+	for(int i:arr) {
+		cout << i << " ";
+	}
+	cout << endl;
+}