Pascal's Triangle
Given an integer numRows, return the first numRows of Pascal's Triangle.
In Pascal's Triangle:
- The first row contains 1.
- Every row starts and ends with 1.
- Each inner element is the sum of the two elements directly above it.
For example, when numRows = 5:
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
Example 1
Input
numRows = 5
Output
[
[1],
[1, 1],
[1, 2, 1],
[1, 3, 3, 1],
[1, 4, 6, 4, 1]
]Explanation
The first row contains 1.
Each following row begins and ends with 1. Every inner value is obtained by adding the two values directly above it.
Example 2
Input
numRows = 1
Output
[
[1]
]Explanation
When only one row is requested, Pascal's Triangle contains a single 1.
Constraints
Hints:
Hint 1
The first and last elements of every row are always 1.
Hint 2
For every inner position:
current[j] = previous[j - 1] + previous[j]
Author & Technical Reviewer
Technically reviewed by: ExamAdda Technical Review Team
Technical Reviewers, ExamAdda
Software engineers at ExamAdda who check every article's definitions, complexity claims and code examples before and after publishing.
Published
Aug 26, 2026
Last updated
Aug 26, 2026
Content Verification Methodology
Definitions and complexity claims were checked against authoritative computer-science references. Code examples were compiled and tested with standard, boundary and edge-case inputs.
Expected Output