81 lines
2.4 KiB
Java
81 lines
2.4 KiB
Java
package DataStructures.Graphs;
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import java.io.BufferedReader;
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import java.io.IOException;
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import java.io.InputStreamReader;
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import java.util.ArrayList;
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import java.util.Arrays;
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/**
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* Given an adjacency list of a graph adj of V no.
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* of vertices having 0 based index.
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* Check whether the graph is bipartite or not.
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*
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* Input :
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* {{0, 1, 0, 1},
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* {1, 0, 1, 0},
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* {0, 1, 0, 1},
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* {1, 0, 1, 0}}
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*
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* Output : YES
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*/
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public class BipartiteGrapfDFS {
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private static boolean bipartite(int V, ArrayList<ArrayList<Integer>>adj, int[] color, int node){
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if(color[node] == -1){
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color[node] = 1;
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}
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for(Integer it : adj.get(node)){
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if(color[it] == -1){
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color[it] = 1-color[node];
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if(bipartite(V, adj, color, it)== false) return false;
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}
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else if(color[it] == color[node]){
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return false;
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}
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}
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return true;
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}
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public static boolean isBipartite(int V, ArrayList<ArrayList<Integer>> adj)
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{
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// Code here
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int[] color = new int[V+1];
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Arrays.fill(color, -1);
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for(int i =0; i< V; i++){
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if(color[i] == -1){
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if(!bipartite(V, adj, color, i)){
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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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public static void main(String[] args) throws IOException {
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BufferedReader read = new BufferedReader(new InputStreamReader(System.in));
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int t = Integer.parseInt(read.readLine().trim());
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while(t-- > 0) {
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String[] S = read.readLine().trim().split(" ");
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int V = Integer.parseInt(S[0]);
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int E = Integer.parseInt(S[1]);
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ArrayList<ArrayList<Integer>> adj = new ArrayList<>();
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for(int i =0;i < V; i++) {
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adj.add(new ArrayList<>());
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}
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for(int i = 0; i < E; i++) {
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String[] s = read.readLine().trim().split(" ");
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int u = Integer.parseInt(s[0]);
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int v = Integer.parseInt(s[1]);
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adj.get(u).add(v);
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adj.get(v).add(u);
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}
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boolean ans = isBipartite(V, adj);
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if(ans)
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System.out.println("YES");
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else
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System.out.println("NO");
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}
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}
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}
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