Adds emrge 2 arrays, array insert at index and is array sorted solutions

Author: omonimus1

c++/array-insert-at-index.cpp

@@ -0,0 +1,11 @@
+// https://practice.geeksforgeeks.org/problems/array-insert-at-index/1/?track=DSA-Foundation-Final-Arrays&batchId=193
+void insertAtIndex(int arr[], int sizeOfArray, int index, int element)
+{
+    // Shift from index to end arrays element by one
+    for(int i = sizeOfArray-1; i >= index; i--)
+    {
+        arr[i] = arr[i-1];
+    }
+    arr[index] = element;
+    
+}

c++/is-array-sorted.cpp

@@ -0,0 +1,36 @@
+// https://practice.geeksforgeeks.org/problems/is-array-sorted/1/?track=DSA-Foundation-Final-Arrays&batchId=193
+bool increasing_order(int arr[], int n)
+{
+    for(int i =1; i < n; i ++)
+    {
+        if(arr[i] < arr[i-1])
+            return false;
+    }
+    return true;
+}
+
+
+bool decreasing_order(int arr[], int n)
+{
+    for(int i =1; i < n; i ++)
+    {
+        if(arr[i] > arr[i-1])
+            return false;
+    }
+    return true;
+}
+
+
+//Complete this function
+int isSorted(int arr[],int n)
+{
+    if(n <=1)
+        return 1;
+    if(n == 2)
+    {
+        if(arr[0] == arr[1])
+            return false;
+        return true;
+    }
+    return (increasing_order(arr, n) || decreasing_order(arr, n) );
+}

c++/merge-two-sorted-arrays.cpp

@@ -0,0 +1,17 @@
+//https://practice.geeksforgeeks.org/problems/merge-two-sorted-arrays-1587115620/1/?track=ppc-arrays&batchId=221
+void merge(int arr1[], int arr2[], int n, int m) 
+{ 
+    
+    int i =n-1, j=0;
+    while(i>=0  && j <m)
+    {    
+        if(arr1[i] > arr2[j])
+            swap(arr1[i], arr2[j]);    
+
+        i--;
+        j++;
+    }
+
+    sort(arr1, arr1+n);
+    sort(arr2, arr2+m);  
+}  

c++/remove-duplicate-elements.cpp

@@ -0,0 +1,16 @@
+// https://practice.geeksforgeeks.org/problems/remove-duplicate-elements-from-sorted-array/1/?track=ppc-arrays&batchId=221
+int remove_duplicate(int A[],int N)
+{
+    set<int>s;
+    for(int i =0; i < N; i++)
+        s.insert(A[i]);
+        
+    int i=0;
+    set<int> ::iterator itr;
+    for(itr= s.begin(); itr != s.end(); itr++)
+    {
+        A[i] = *itr;
+        i++;
+    }
+    return i; 
+}