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keep code consistent

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Evan Ferrao 2026-02-14 15:24:35 +05:30 committed by GitHub
parent 046371022d
commit c583b04984
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2 changed files with 65 additions and 68 deletions
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75
Graphs/CycleDetectionBFS.java
View File

@ -1,67 +1,68 @@
import java.util.*;
import java.io.*;
public class CycleDetectionBFS {
class Main {
static class Pair {
int first;
int second;
// helper structure
static class Node{
int node;
int parent;
Pair(int first, int second) {
this.first = first;
this.second = second;
Node(int node, int parent){
this.node = node;
this.parent = parent;
}
}
public static boolean bfs(int src, int V, ArrayList<ArrayList<Integer>> adj,boolean[] vis) {
public static boolean bfs(int src, int V,
ArrayList<ArrayList<Integer>> adj,
boolean visited[]){
vis[src] = true;
Queue<Pair> q = new LinkedList<>();
q.add(new Pair(src, -1));
visited[src] = true;
while (!q.isEmpty()) {
int node = q.peek().first;
int parent = q.peek().second;
q.remove();
Queue<Node> q = new LinkedList<>();
q.add(new Node(src, -1));
for (int adjacentNode : adj.get(node)) {
if (!vis[adjacentNode]) {
vis[adjacentNode] = true;
q.add(new Pair(adjacentNode, node));
while(!q.isEmpty()){
Node cur = q.poll();
int u = cur.node;
int par = cur.parent;
for(int v : adj.get(u)){
if(!visited[v]){
visited[v] = true;
q.add(new Node(v, u));
}
// everything except this 'else if' statement is normal BFS
else if (adjacentNode != parent) {
return true; // cycle detected
else if(v != par){
return true; // cycle
}
}
}
return false;
}
public static boolean isCycle(int V, ArrayList<ArrayList<Integer>> adj) {
public static boolean isCycle(int V, ArrayList<ArrayList<Integer>> adj){
boolean[] vis = new boolean[V];
boolean visited[] = new boolean[V];
for (int i = 0; i < V; i++) {
if (!vis[i]) {
if (bfs(i, V, adj, vis)) {
return true;
}
for(int i=0;i<V;i++){
if(!visited[i]){
if(bfs(i, V, adj, visited)) return true;
}
}
return false;
}
public static void main(String[] args) {
// ================= DRIVER =================
public static void main(String args[]){
int V = 5;
ArrayList<ArrayList<Integer>> adj = new ArrayList<>();
for (int i = 0; i < V; i++) {
adj.add(new ArrayList<>());
}
for(int i=0;i<V;i++) adj.add(new ArrayList<>());
// Undirected graph edges
// Undirected graph
adj.get(0).add(1);
adj.get(1).add(0);
@ -71,12 +72,12 @@ public class CycleDetectionBFS {
adj.get(2).add(3);
adj.get(3).add(2);
adj.get(3).add(1); // creates a cycle
adj.get(3).add(1);
adj.get(1).add(3);
adj.get(3).add(4);
adj.get(4).add(3);
System.out.printf(isCycle(V, adj) ? "Cycle detected" : "No cycle detected");
System.out.printf(isCycle(V, adj) ? "Cycle detected\n" : "No cycle detected\n");
}
}

58
Graphs/CycleDetectionDFS.java
View File

@ -1,64 +1,60 @@
import java.util.*;
import java.io.*;
public class CycleDetectionDFS {
class Main {
static class Pair {
// helper structure
static class Node{
int node;
int parent;
Pair(int node, int parent) {
Node(int node, int parent){
this.node = node;
this.parent = parent;
}
}
public static boolean dfs(Pair current, boolean[] vis, ArrayList<ArrayList<Integer>> adj) {
public static boolean dfs(Node cur, boolean visited[],
ArrayList<ArrayList<Integer>> adj){
int node = current.node;
int parent = current.parent;
int u = cur.node;
int par = cur.parent;
vis[node] = true;
visited[u] = true;
for (int adjacentNode : adj.get(node)) {
if (!vis[adjacentNode]) {
if (dfs(new Pair(adjacentNode, node), vis, adj)) {
return true;
}
for(int v : adj.get(u)){
if(!visited[v]){
if(dfs(new Node(v, u), visited, adj)) return true;
}
// everything except this 'else if' statement is normal DFS
else if (adjacentNode != parent) {
return true;
else if(v != par){
return true; // cycle
}
}
return false;
}
public static boolean isCycle(int V, ArrayList<ArrayList<Integer>> adj) {
public static boolean isCycle(int V, ArrayList<ArrayList<Integer>> adj){
boolean[] vis = new boolean[V];
boolean visited[] = new boolean[V];
for (int i = 0; i < V; i++) {
if (!vis[i]) {
if (dfs(new Pair(i, -1), vis, adj)) {
return true;
}
for(int i=0;i<V;i++){
if(!visited[i]){
if(dfs(new Node(i, -1), visited, adj)) return true;
}
}
return false;
}
public static void main(String[] args) {
// ================= DRIVER =================
public static void main(String args[]){
int V = 5;
ArrayList<ArrayList<Integer>> adj = new ArrayList<>();
for (int i = 0; i < V; i++) {
adj.add(new ArrayList<>());
}
for(int i=0;i<V;i++) adj.add(new ArrayList<>());
// Undirected graph edges
// Undirected graph
adj.get(0).add(1);
adj.get(1).add(0);
@ -68,12 +64,12 @@ public class CycleDetectionDFS {
adj.get(2).add(3);
adj.get(3).add(2);
adj.get(3).add(1); // creates a cycle
adj.get(3).add(1);
adj.get(1).add(3);
adj.get(3).add(4);
adj.get(4).add(3);
System.out.printf(isCycle(V, adj) ? "Cycle detected" : "No cycle detected");
System.out.printf(isCycle(V, adj) ? "Cycle detected\n" : "No cycle detected\n");
}
}