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Insertion Sort Algorithm

Certification: Intermediate Level Accuracy: 50% Submissions: 8 Points: 10

Write a Python program that implements the Insertion Sort algorithm to sort a list of integers in ascending order. Insertion Sort builds the final sorted array one item at a time, taking one element from the input data in each iteration and inserting it into its correct position in the already sorted part of the array.

Example 1
    
  
  • Input: [12, 11, 13, 5, 6]
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  • Output: [5, 6, 11, 12, 13]
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  • Explanation: 
    
      
      
    • Step 1: Take the input array [12, 11, 13, 5, 6].
      • 
      
    • Step 2: Start with [12] as the sorted portion and [11, 13, 5, 6] as unsorted.
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    • Step 3: Take 11, compare with sorted elements, and insert: [11, 12] | [13, 5, 6].
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    • Step 4: Take 13, compare and insert: [11, 12, 13] | [5, 6].
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    • Step 5: Take 5, compare and insert: [5, 11, 12, 13] | [6].
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    • Step 6: Take 6, compare and insert: [5, 6, 11, 12, 13].
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    • Step 7: Return the sorted array [5, 6, 11, 12, 13].
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    •
Example 2
    
  
  • Input: [64, 34, 25, 12, 22, 11, 90]
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  • Output: [11, 12, 22, 25, 34, 64, 90]
    • 
  
  • Explanation: 
    
      
      
    • Step 1: Take the input array [64, 34, 25, 12, 22, 11, 90].
      • 
      
    • Step 2: Start with [64] as the sorted portion and [34, 25, 12, 22, 11, 90] as unsorted.
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    • Step 3: Take 34, compare with sorted elements, and insert: [34, 64] | [25, 12, 22, 11, 90].
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    • Step 4: Take 25, compare and insert: [25, 34, 64] | [12, 22, 11, 90].
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    • Step 5: Continue this process for all elements.
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    • Step 6: Return the sorted array [11, 12, 22, 25, 34, 64, 90].
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    •
Constraints
    
  
  • 1 ≤ len(arr) ≤ 10^3
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  • -10^6 ≤ arr[i] ≤ 10^6
    • 
  
  • Time Complexity: O(n²), where n is the length of the array
    • 
  
  • Space Complexity: O(1)
    •
ArraysNumberControl StructuresIBMHCL Technologies
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Hint
Solution

Solution Hints

    
  
  • Iterate through the array starting from the second element
    • 
  
  • For each element, compare it with all elements in the sorted part of the array
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  • Shift all elements greater than the current element one position ahead
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  • Insert the current element at its correct position in the sorted part
    • 
  
  • The sorted part of the array grows with each iteration
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  • Optimize by using binary search to find the insertion position
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  • For small arrays or nearly sorted arrays, Insertion Sort can be very efficient
    •

Steps to solve by this approach:

 Step 1: Create a copy of the input array to avoid modifying the original.
 Step 2: Start from the second element (index 1) and iterate through the array.
 Step 3: For each element, store its value in a variable 'key'.
 Step 4: Compare key with all elements in the sorted portion (0 to i-1).
 Step 5: Shift elements that are greater than key one position ahead.
 Step 6: Insert the key at its correct position in the sorted sequence.
 Step 7: Return the sorted array.

Submitted Code :