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Commit 9a474c0

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1 parent 0849e09 commit 9a474c0

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7 files changed

+583
-46
lines changed

7 files changed

+583
-46
lines changed

‎DSAPractice/graph/BFS.java‎

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import java.io.*;
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import java.util.*;
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class BFS {
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static BufferedReader br;
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static StringTokenizer st;
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static int nextInt() throws IOException {
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return Integer.parseInt(next());
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}
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static String next() throws IOException {
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while (st == null || !st.hasMoreTokens()) {
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st = new StringTokenizer(br.readLine());
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}
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return st.nextToken();
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}
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static long nextLong() throws IOException {
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return Long.parseLong(next());
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}
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public static void main(String args[]) throws IOException {
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br = new BufferedReader(new InputStreamReader(System.in));
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int t = nextInt();
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while (t-- > 0) {
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input();
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}
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br.close();
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}
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public static void input() throws IOException {
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int vertex = nextInt();
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int edges = nextInt();
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List<List<Integer>> adjecencyList = new ArrayList<>();
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for (int i = 0; i < vertex + 1; i++) {
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adjecencyList.add(new ArrayList<>());
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}
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for (int i = 0; i < edges; i++) {
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int source = nextInt();
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int destination = nextInt();
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adjecencyList.get(source).add(destination);
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adjecencyList.get(destination).add(source);// because this is undirected
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}
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System.out.println(adjecencyList);
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int vis[] = new int[vertex + 1];
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bfs(vis, adjecencyList);
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}
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public static void bfs(int[] vis, List<List<Integer>> adj) {
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List<Integer> bfs = new ArrayList<>();
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for (int i = 1; i < vis.length; i++) {
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if (vis[i] == 0) {
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Queue<Integer> trav = new LinkedList<>();
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trav.add(i);
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vis[i] = 1;
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while (!trav.isEmpty()) {
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int node = trav.poll();
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bfs.add(node);
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for (int it : adj.get(node)) {
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if (vis[it] == 0) {
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vis[it] = 1;
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trav.add(it);
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}
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}
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}
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}
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}
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System.out.println("The bfs is:");
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System.out.println(bfs);
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}
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}
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import java.io.*;
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import java.util.*;
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class Bipartitebfscolouring {
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static BufferedReader br;
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static StringTokenizer st;
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static int nextInt() throws IOException {
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return Integer.parseInt(next());
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}
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static String next() throws IOException {
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while (st == null || !st.hasMoreTokens()) {
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st = new StringTokenizer(br.readLine());
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}
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return st.nextToken();
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}
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static long nextLong() throws IOException {
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return Long.parseLong(next());
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}
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public static void main(String args[]) throws IOException {
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br = new BufferedReader(new InputStreamReader(System.in));
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int t = nextInt();
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while (t-- > 0) {
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input();
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}
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br.close();
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}
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public static void input() throws IOException {
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int vertices = nextInt();
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int edges = nextInt();
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List<List<Integer>> adj = new ArrayList<>();
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for (int i = 0; i < vertices + 1; i++) {
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adj.add(new ArrayList<>());
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}
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for (int i = 0; i < edges; i++) {
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int source = nextInt();
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int destination = nextInt();
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adj.get(source).add(destination);
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adj.get(destination).add(source);
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}
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int vis[] = new int[vertices + 1];
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boolean result = bfs(vis, adj, vertices);
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System.out.println(result);
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}
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static boolean bfs(int[] vis, List<List<Integer>> adj, int vertices) {
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int colour[] = new int[vertices + 1];
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for (int i = 1; i < vertices + 1; i++) {
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colour[i] = -1;
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}
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for (int i = 1; i < vis.length; i++) {
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if (vis[i] == 0) {
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if (colour[i] == -1) {
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if (!bfs(adj, i, colour)) {
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return false;
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}
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}
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}
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}
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return true;
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}
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static boolean bfs(List<List<Integer>> adj, int node, int[] colour) {
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Queue<Integer> q = new LinkedList<>();
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q.add(node);
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colour[node] = 1;
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while (!q.isEmpty()) {
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int no = q.poll();
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for (int it : adj.get(no)) {
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if (colour[it] == -1) {
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colour[it] = 1 - colour[no];
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q.add(it);
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} else if (colour[it] == colour[no]) {
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return false;
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}
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}
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}
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return true;
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}
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}

‎DSAPractice/graph/DFS.java‎

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import java.io.*;
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import java.util.*;
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class DFS {
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static BufferedReader br;
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static StringTokenizer st;
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static int nextInt() throws IOException {
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return Integer.parseInt(next());
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}
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static String next() throws IOException {
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while (st == null || !st.hasMoreTokens()) {
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st = new StringTokenizer(br.readLine());
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}
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return st.nextToken();
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}
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static long nextLong() throws IOException {
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return Long.parseLong(next());
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}
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public static void main(String args[]) throws IOException {
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br = new BufferedReader(new InputStreamReader(System.in));
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int t = nextInt();
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while (t-- > 0) {
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input();
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}
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br.close();
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}
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public static void input() throws IOException {
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int vertices = nextInt();
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int edges = nextInt();
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List<List<Integer>> adj = new ArrayList<>();
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for (int i = 0; i < vertices + 1; i++) {
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adj.add(new ArrayList<>());
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}
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for (int i = 0; i < edges; i++) {
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int source = nextInt();
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int destin = nextInt();
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adj.get(source).add(destin);
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adj.get(destin).add(source);
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}
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int vis[] = new int[vertices + 1];
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List<Integer> dfslist = new ArrayList<>();
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for (int i = 1; i < vis.length; i++) {
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if (vis[i] == 0) {
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dfs(i, adj, vis, dfslist);
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}
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}
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System.out.println(adj);
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System.out.println(dfslist);
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}
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public static void dfs(int index, List<List<Integer>> adj, int[] vis, List<Integer> dfslist) {
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dfslist.add(index);
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vis[index] = 1;
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for (int i : adj.get(index)) {
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if (vis[i] == 0) {
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dfs(i, adj, vis, dfslist);
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}
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}
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}
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}
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import java.util.*;
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import java.io.*;
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class Node {
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int par, child;
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Node(int par, int child) {
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this.child = child;
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this.par = par;
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}
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}
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// using bfs
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public class DetectCycleInUndirectedGraph {
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static StringTokenizer st;
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static BufferedReader br;
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static String next() throws IOException {
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while (st == null || !st.hasMoreTokens()) {
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st = new StringTokenizer(br.readLine());
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}
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return st.nextToken();
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}
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static int nextInt() throws IOException {
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return Integer.parseInt(next());
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}
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static long nextLong() throws IOException {
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return Long.parseLong(next());
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}
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public static void main(String[] args) throws IOException {
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br = new BufferedReader(new InputStreamReader(System.in));
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int t = nextInt();
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while (t-- > 0) {
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input();
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}
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br.close();
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}
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static void input() throws IOException {
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int vertices = nextInt();
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int edges = nextInt();
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List<List<Integer>> adj = new ArrayList<>();
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for (int i = 0; i < vertices + 1; i++) {
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adj.add(new ArrayList<>());
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}
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for (int i = 0; i < edges; i++) {
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int source = nextInt();
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int destination = nextInt();
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adj.get(source).add(destination);
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adj.get(destination).add(source);
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}
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int vis[] = new int[vertices + 1];
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System.out.println(adj);
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boolean result = bfs(adj, vis);
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System.out.println(result);
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}
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static boolean bfs(List<List<Integer>> adj, int vis[]) {
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// List<Integer> bfs = new ArrayList<>();
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for (int i = 1; i < vis.length; i++) {
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if (vis[i] == 0) {
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if (cycle(i, adj, vis)) {
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return true;
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}
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}
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}
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return false;
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}
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static boolean cycle(int ind, List<List<Integer>> adj, int[] vis) {
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Queue<Node> t = new LinkedList<>();
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t.add(new Node(-1, ind));
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while (!t.isEmpty()) {
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int par = t.peek().par;
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int node = t.peek().child;
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t.remove();
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for (int it : adj.get(node)) {
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if (vis[it] == 0) {
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t.add(new Node(node, it));
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vis[it] = 1;
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} else if (par != it) {
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return true;
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}
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}
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}
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return false;
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}
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}

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