Pascal's Triangle Construction

You are provided with an integer 'N'. Your task is to generate a 2-D list representing Pascal’s triangle up to the 'N'th row.

Pascal's triangle is a triangular array where each element is the sum of the two directly above it from the preceding row, representing binomial coefficients.

Example:

Input:

N = 4

Output:

[ [1], [1, 1], [1, 2, 1], [1, 3, 3, 1] ]

Explanation:

In the third row, for example, the second element is calculated as follows: 2 = 1 + 1. Similarly, in the fourth row, the numbers 3 are derived: 3 = 1 + 2 and 3 = 2 + 1.

Constraints:

1 ≤ T ≤ 40

1 ≤ N ≤ 50

Time Limit: 1 sec

Question

Pascal's Triangle Construction

You are provided with an integer 'N'. Your task is to generate a 2-D list representing Pascal’s triangle up to the 'N'th row.

Pascal's triangle is a triangular array where each element is the sum of the two directly above it from the preceding row, representing binomial coefficients.

Example:

Input:

N = 4

Output:

[ [1], [1, 1], [1, 2, 1], [1, 3, 3, 1] ]

Explanation:

In the third row, for example, the second element is calculated as follows: 2 = 1 + 1. Similarly, in the fourth row, the numbers 3 are derived: 3 = 1 + 2 and 3 = 2 + 1.

Constraints:

1 ≤ T ≤ 40
1 ≤ N ≤ 50
Time Limit: 1 sec

Accepted Answer

Generate Pascal's triangle up to the Nth row using a 2-D list.

Iterate through each row up to N, starting with [1] as the first row.
Calculate each element in a row by summing the two elements directly above from the previous row.
Append each row to the 2-D list until reaching the Nth row.
Example: For N = 4, the output would be [ [1], [1, 1], [1, 2, 1], [1, 3, 3, 1] ]

Accepted Answer

        answer = []
        for row in range(numRows):
            ans = 1
            ansRow = [1]
            for col in range(row):
                ans *= row - col
                ans //= col + 1
                ansRow.append(ans)
            answer.append(ansRow)
        return answer

Asked in Capgemini