How should I practice Drawing Edge?

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

Is Drawing Edge associated with WeRide?

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

Drawing Edge

WeRide● EasyFULLTIMEOA

Problem statement

Given n labeled nodes, count the distinct simple undirected graphs that can be drawn on them.

For every unordered pair of distinct nodes, an edge may be present or absent.
A node cannot have an edge to itself.
The graph does not have to be connected.

Two graphs are distinct if at least one unordered pair has a different edge state. Return the number of distinct graphs modulo 10^9 + 7.

Function

drawingEdge(n: int) → int

Examples

Example 1

n = 3return = 8

There are three possible undirected edges. Each one can independently be present or absent, so there are 2^3 = 8 distinct graphs.

Example 2

n = 4return = 64

Four nodes have six unordered pairs, so the number of graphs is 2^6 = 64.

Constraints

1 <= n <= 10^9