Graphs in Java
Practice this questionWANT TO UNDERSTAND THE CONCEPT FIRST?Learn Graphs in Java
Graph representation
- adjacency list using
List<List<Integer>> - adjacency matrix for dense graphs
Problems to practice
- Number of Islands
- Clone Graph
- Course Schedule
- Topological Sort
- DFS/BFS traversal
- Shortest Path (BFS / Dijkstra)
- Union-Find problems
BFS example
Queue<Integer> queue = new LinkedList<>();
Set<Integer> visited = new HashSet<>();
queue.offer(start);
visited.add(start);
while (!queue.isEmpty()) {
int node = queue.poll();
for (int next : graph.get(node)) {
if (!visited.contains(next)) {
visited.add(next);
queue.offer(next);
}
}
}Adapted from 15_DSA_JAVA.md · “9. Graphs in Java”. Code examples are study fragments. Difficulty and core labels are editorial estimates; version-specific behavior should be checked against your project.