Create MergeSortedArrays.cpp

This is the solution for Merging 2 sorted arrays in C++ language.

C++/MergeSortedArrays.cpp

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+#include <vector>
+#include <algorithm>
+using namespace std;
+
+class Solution {
+public:
+    // Function to swap elements if the element in arr1 is greater than the element in arr2
+    void swapIfGreater(vector<int>& arr1, vector<int>& arr2, int ind1, int ind2) {
+        if (arr1[ind1] > arr2[ind2]) {
+            swap(arr1[ind1], arr2[ind2]); //mno loop so no increment and decrement
+        }
+    }
+
+    // Function to merge two sorted arrays
+    void merge(vector<int>& arr1, int n, vector<int>& arr2, int m) {
+        int len = n + m;
+
+        // Initial gap
+        int gap = (len / 2) + (len % 2);
+
+        while (gap > 0) {
+            int left = 0;
+            int right = left + gap;
+
+            while (right < len) {
+                // Case 1: left in arr1 and right in arr2
+                if (left < n && right >= n) {
+                    swapIfGreater(arr1, arr2, left, right - n);
+                }
+                // Case 2: both pointers in arr2
+                else if (left >= n) {
+                    swapIfGreater(arr2, arr2, left - n, right - n); //you know why right - n
+                }
+                // Case 3: both pointers in arr1
+                else {
+                    swapIfGreater(arr1, arr1, left, right);
+                }
+                left++;
+                right++;
+            }
+
+            // Break if iteration gap=1 is completed
+            if (gap == 1) break;
+
+            // Otherwise, calculate new gap
+            gap = (gap / 2) + (gap % 2);
+        }
+
+        // Copy remaining elements of arr2 to arr1 if any
+        for (int i = 0; i < m; i++) {
+            arr1[n + i] = arr2[i]; //arr1 taking additional elements from array 2 to store
+        }
+    }
+};