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Merge Two Sorted Arrays

Certification: Basic Level Accuracy: 40% Submissions: 5 Points: 5

Write a C program to merge two sorted arrays into a single sorted array. Given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and nums2 respectively. The final sorted array should be stored inside the array nums1. To accommodate this, nums1 has a length of m + n, where the first m elements denote the elements that should be merged, and the last n elements are set to 0 and should be ignored.

Example 1
    
  
  • Input: nums1 = [1,2,3,0,0,0], m = 3, nums2 = [2,5,6], n = 3
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  • Output: [1,2,2,3,5,6]
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  • Explanation: The arrays [1,2,3] and [2,5,6] are merged to form [1,2,2,3,5,6].
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Example 2
    
  
  • Input: nums1 = [1], m = 1, nums2 = [], n = 0
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  • Output: [1]
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  • Explanation: Since nums2 is empty, nums1 remains unchanged.
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Constraints
    
  
  • nums1.length == m + n
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  • nums2.length == n
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  • 0 ≤ m, n ≤ 200
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  • 1 ≤ m + n ≤ 200
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  • -10^9 ≤ nums1[i], nums2[j] ≤ 10^9
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  • Time Complexity: O(m + n)
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  • Space Complexity: O(1) - no extra space should be used
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ArraysWiproIBM
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Hint
Solution

Solution Hints

    
  
  • nums1 has enough space at the end, start filling nums1 from the end
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  • Use two pointers to track the current positions in the valid portions of nums1 and nums2
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  • Compare elements from both arrays and place the larger one at the end of nums1
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  • Continue this process until all elements are merged
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  • Be careful about handling cases where one array is exhausted before the other
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  • Remember that you need to handle any remaining elements in nums2
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Steps to solve by this approach:

 Step 1: Initialize three pointers - i pointing to the last element in nums1 array (m-1), j pointing to the last element in nums2 array (n-1), and k pointing to the last position in the merged array (m+n-1).

 Step 2: Compare elements at nums1[i] and nums2[j].

 Step 3: Place the larger element at position nums1[k] and decrement the respective pointers.

 Step 4: Continue this process until we exhaust either nums1 or nums2.

 Step 5: If there are remaining elements in nums2, copy them to the beginning of nums1.

 Step 6: No need to handle remaining elements in nums1 as they are already in the correct position.

 Step 7: The array nums1 now contains the merged result.

Submitted Code :