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# 1971. Find if Path Exists in Graph
from collections import defaultdict
"""
there is a bidirectional graph with 'n' vertices where each vertex is labeled
from 0 to 'n - 1' inclusive. the edges in the graph are rpresented as a 2d
integer array 'edges', where each 'edgies[i] = [ui, vi]', denotes a
bidirectional edge between vertex 'ui' and vertex 'vi'. every vertex pair is
connected by at most one edge, and no vertex has an edge to itself.
"""
class Solution(object):
def validPath(self, n, edges, source, destination):
"""
:type n: int
:type edges: List[List[int]]
:type source: int
:type destination: int
:rtype: bool
"""
neighbors = defaultdict(list)
for n1, n2 in edges:
neighbors[n1].append(n2)
neighbors[n2].append(n1)
def dfs(node, destination, seen):
if node == destination:
return True
if node in seen:
return False
seen.add(node)
for n in neighbors[node]:
if dfs(n, destination, seen):
return True
return False
seen = set()
return dfs(source, destination, seen)
if __name__ == "__main__":
obj = Solution()
print(obj.validPath(n=3, edges=[[0, 1], [1, 2], [2, 0]], source=0, destination=2))
print(
obj.validPath(
n=6, edges=[[0, 1], [0, 2], [3, 5], [5, 4], [4, 3]], source=0, destination=5
)
)
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