added merge_without_extra_space

Author: geekySapien

DSA 450 GFG/merge_without_extra_space.cpp

@@ -0,0 +1,124 @@
+//Link to the Problem:
+//https://practice.geeksforgeeks.org/problems/merge-two-sorted-arrays-1587115620/1
+ 
+//Sample Test Case
+ 
+/*
+ 
+Input: 
+n = 4, arr1[] = [1 3 5 7] 
+m = 5, arr2[] = [0 2 6 8 9]
+ 
+ 
+Output: 
+arr1[] = [0 1 2 3]
+arr2[] = [5 6 7 8 9]
+ 
+ 
+we start from end of first array and start of second array
+i.e i points to index 3 of first array and j points to index 0 of second array
+ 
+i=3
+j=0
+ 
+since 7>0, we swap both of them, now array becomes
+ 
+arr1[] = [1 3 5 0] 
+arr2[] = [7 2 6 8 9]
+ 
+i=2
+j=1
+ 
+since 5>2
+ 
+arr1[] = [1 3 2 0] 
+arr2[] = [7 5 6 8 9]
+ 
+i=1
+j=2
+ 
+3 is not greater than 6, for loop breaks and we come out of the loop
+ 
+ 
+Now we sort  the arrays and get the o/p as follows:
+ 
+arr1[] = [0 1 2 3]
+arr2[] = [5 6 7 8 9]
+ 
+*/
+ 
+#include <bits/stdc++.h>
+using namespace std;
+ 
+class Solution
+{
+public:
+    void merge(int arr1[], int arr2[], int n, int m)
+    {
+ 
+        // Starting from last index of first array and first index of second arary
+        int i = n - 1;
+        int j = 0;
+ 
+        //iterating till the small array is traversed [Note that AND operator is
+        //used]
+        while (i >= 0 && j < m)
+        {
+            if (arr1[i] > arr2[j])
+            {
+                swap(arr1[i], arr2[j]);
+                i--;
+                j++;
+            }
+            else
+            {
+                break;
+            }
+        }
+ 
+        //Sorting both the arrays as the order in which element occured would
+        //have changed
+        sort(arr1, arr1 + n);
+        sort(arr2, arr2 + m);
+    }
+};
+ 
+int main()
+{
+    int t;
+    cin >> t;
+    while (t--)
+    {
+ 
+        //n -> Size of first Array
+        //m -> Size of Second Array
+        //i -> Iterator
+        //arr1 -> First Array
+        //arr2 ->Second Array
+        int n, m, i;
+        cin >> n >> m;
+        int arr1[n], arr2[m];
+        for (i = 0; i < n; i++)
+        {
+            cin >> arr1[i];
+        }
+        for (i = 0; i < m; i++)
+        {
+            cin >> arr2[i];
+        }
+ 
+        //Creating an instance of class
+        Solution ob;
+        ob.merge(arr1, arr2, n, m);
+        for (i = 0; i < n; i++)
+        {
+            cout << arr1[i] << " ";
+        }
+        for (i = 0; i < m; i++)
+        {
+            cout << arr2[i] << " ";
+        }
+        cout << "\n";
+    }
+    return 0;
+}