Pascal triangle-Coding question asked by Google, Amazon, Nagarro

3 min readJun 22, 2022


Problem statement:

Given an integer numRows, return the first numRows of Pascal’s triangle.

Input Format:

Number of Rows in Pascal Triangle

Output Format:

List containing arrays representing rows of Pascal Triangle

Sample Input:


Sample Output:



the iterative approach to constructing Pascal’s triangle can be classified as dynamic programming because we construct each row based on the previous row.

First, we generate the overall triangle list, which will store each row as a sublist. Then, we check for the special case of 00, as we would otherwise return [1][1]. Since numRowsnumRows is always greater than 00, we can initialize triangle with [1][1] as its first row, and proceed to fill the rows as follows:

Time complexity: O(NumRows²)

Space complexity: O(1)


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