Eulerian Path Existence

Problem

Decide whether an undirected graph with n nodes has an Eulerian path: a trail that visits every edge exactly once.

edges is a list of [u, v] pairs. Ignoring isolated nodes, the graph must be connected and have either 0 or 2 odd-degree nodes. Return a boolean.

Hint

Connectivity of all non-isolated nodes plus 0 or 2 odd degrees is necessary and sufficient.

case 1

in: [4,[[0,1],[1,2],[2,3]]]

expected: true

case 2

in: [3,[[0,1],[1,2],[2,0]]]

expected: true

case 3

in: [4,[[0,1],[0,2],[0,3]]]

expected: false

case 4

in: [6,[[0,1],[1,2],[3,4],[4,5]]]

expected: false

case 5

in: [1,[]]

expected: true

Starter codePython

def has_eulerian_path(n, edges):
    # Your code here
    pass

5 test cases · run your code against them in the editor