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

3 min readJun 22, 2022

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# 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:

`5`

Sample Output:

`[[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]]`

# Approach:

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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