buglife spoj Time limit exceeded java -

any hint avoid getting time limit exceeded problem :_ http://www.spoj.com/problems/buglife/

how optimize code

is there faster method reading input

these methods reading input :_ http://ideone.com/gtsiac

my solution :_

import java.io.*; import java.util.*;  public class buglife {     static int first;     static arraylist[] graph = new arraylist[2000];     static int[] colour = new int[2000];     static int[] queue = new int[2000];     static int start;     static int index;     static int current;      public static boolean bfs(int f) {           (int p = 0; p < first; p++) {         if (colour[p] != f && colour[p] != f + 1) {         int x;         start = 0;         index = 0;         queue[index++] = p;         colour[p] = f;               while (start < index) {                     current = queue[start++];                     (int = 0; < graph[current].size(); i++) {                         x = (integer) graph[current].get(i);                         if (colour[x] != f && colour[x] != f + 1) {                             if (colour[current] == f) {                                 colour[x] = f + 1;                             } else if (colour[current] == f + 1) {                                 colour[x] = f;                             }                              queue[index++] = x;                         } else if (colour[current] == colour[x]) {                              return false;                         }                      }                 }              }         }         return true;     }      public static void main(string[] args) throws ioexception, exception {         int second;         int one, two;         printwriter out = new printwriter(new bufferedwriter(                 new outputstreamwriter(system.out)));          int test = nextint();         int j, k, i;         (i = 1; <= test; i++) {             first = nextint();             second = nextint();             (k = 0; k < first; k++)                 graph[k] = new arraylist();              (j = 0; j < second; j++) {                  1 = nextint();                 2 = nextint();                 graph[one - 1].add(two - 1);                 graph[two - 1].add(one - 1);             }              out.println("scenario #" + + ":");             if (bfs( 2 * i) == false) {                 out.println("suspicious bugs found!");             } else {                 out.println("no suspicious bugs found!");             }          }         out.flush();     }     } 

you can not solve using bfs, problem bipartite graph

just @ wikipedia

i solved problem more year ago. my profile