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Problem

Submissions

Pascal's Triangle

Contributed by

Dhruv Sharma

Easy

0/40

Avg time to solve 20 mins

Success Rate 80 %

273 upvotes

Problem Statement

You are given an integer N. Your task is to return a 2-D ArrayList containing the pascal’s triangle till the row N.

A Pascal's triangle is a triangular array constructed by summing adjacent elements in preceding rows. Pascal's triangle contains the values of the binomial coefficient. For example in the figure below.

For example, given integer N= 4 then you have to print.

1  
1 1 
1 2 1 
1 3 3 1

Here for the third row, you will see that the second element is the summation of the above two-row elements i.e. 2=1+1, and similarly for row three 3 = 1+2 and 3 = 1+2.

Detailed explanation ( Input/output format, Notes, Constraints, Images )

Input format :

The first line of input contains an integer ‘T’ denoting the number of test cases.
The first line of each test case contains a single integer N denoting the row till which you have to print the pascal’s triangle.

Output format :

For each test case, return the 2-D array/list containing the pascal’s triangle till the row N.

Note:

You do not need to print anything; it has already been taken care of. Just implement the given function.

Constraints:

1 <= T <= 40
1 <= N <= 50

Time Limit: 1 sec

Sample Input 1 :

Sample Output 1 :

Explanation of The Sample Input 1:

For the first test case:
The given integer N = 1 you have to print the triangle till row 1 so you just have to output 1.

For the second test case:
The given integer N = 2 you have to print the triangle till row 2 so you have to output 
1
1 1

For the third test case
The given integer N = 3 you have to print the triangle till row 3 so you have to output 
1
1 1
1 2 1

Sample Input 2 :

Sample Output 2 :

1 
1 1 
1 2 1
1 3 3 1 
1 
1 1 
1 2 1 
1 3 3 1 
1 4 6 4 1
1 
1 1 
1 2 1 
1 3 3 1 
1 4 6 4 1
1 5 10 10 5 1

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