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Generate Pascal's Triangle Up to N Rows

Certification: Basic Level Accuracy: 56.25% Submissions: 64 Points: 10

Write a Python program that generates Pascal's Triangle up to N rows.

Example 1
    

  • Input: N = 5
    • 

  • Output: 
     [1]
     [1, 1]

     [1, 2, 1]

     [1, 3, 3, 1]

     [1, 4, 6, 4, 1]
    • 

  • Explanation: 

      

    • Step 1: Start with the first row as [1].
      • 

    • Step 2: To generate the next row, add adjacent elements of the previous row.
      • 

    • Step 3: Each row starts and ends with 1.
      • 

    • Step 4: Continue this process until we have N rows.
      • 

    

    •
Example 2
    

  • Input: N = 3
    • 

  • Output: 
    [1]

    [1, 1]

    [1, 2, 1]
    • 

  • Explanation: 

      

    • Step 1: Start with the first row as [1].
      • 

    • Step 2: Generate the second row as [1, 1].
      • 

    • Step 3: Generate the third row by adding adjacent elements of the second row: [1, 1+1, 1] = [1, 2, 1].
      • 

    

    •
Constraints
    

  • 0 ≤ N ≤ 30
    • 

  • Time Complexity: O(n²)
    • 

  • Space Complexity: O(n²)
    •
ArraysControl StructuresGoogleGoldman Sachs
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Hint
Solution

Solution Hints

    
  
  • Start with the first row as [1]
    • 
  
  • Each row can be built using: row[i] = prev_row[i-1] + prev_row[i] for middle elements
    •

The following are the steps to solve: 

  •  Initialize an empty list to store the triangle
  •  For each row, create a new list with the correct number of elements

  •  The first and last elements of each row are always 1

  •  Calculate middle elements using the formula: row[j] = previous_row[j-1] + previous_row[j]

  •  Add each row to the triangle

  •  Return the completed triangle

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