How should I practice Drawing Edge?

Start by reading the full statement, solve the visible examples, then compare the pattern against related IBM online assessment problems in FastPrep.

Is Drawing Edge associated with IBM?

FastPrep tags this as a IBM online assessment coding practice problem when the problem catalog has that company and stage context.

Drawing Edge

IBM● EasyFULLTIMEINTERNOA

Learn

Problem statement

You are given n labeled vertices. For every unordered pair of distinct vertices, you may either draw one undirected edge between them or leave them disconnected.

A graph may be disconnected. Two graphs are different when at least one pair of vertices has a different edge choice.

Return the number of distinct simple undirected graphs that can be formed, modulo 10^9 + 7.

Complete drawingEdge with the parameter int n and return the result as an int.

Function

drawingEdge(n: int) → int

Examples

Example 1

n = 4return = 64

Four vertices determine 4 * 3 / 2 = 6 possible edges. Each edge can be absent or present independently, so the number of graphs is 2^6 = 64.

Example 2

n = 2return = 2

There is one possible edge between the two vertices. It can be absent or present, so there are 2 graphs.

Constraints

1 <= n <= 10^9