UVA - 11205 - The broken pedometer

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder sb = new StringBuilder();
        int cases=Integer.parseInt(br.readLine());
        for(int i=0;i<cases;i++){
            int leds=Integer.parseInt(br.readLine());
            int numbers=Integer.parseInt(br.readLine());
            int[] arr=new int[numbers];
            for(int j=0;j<numbers;j++){
                StringBuilder str=new StringBuilder();
                StringTokenizer st=new StringTokenizer(br.readLine());
                for(int l=0;l<leds;l++){
                    str.append(st.nextToken());
                }
                arr[j]=Integer.parseInt(str.toString(),2);
            }
            int min=Integer.MAX_VALUE;
            for(int j=1;j<Math.pow(2, leds);j++){
                if(checkUnique(j,leds,arr)){
                    int counter=countbits(j);
                    if(min>counter)
                        min=counter;
                }
            }
            sb.append(min).append("\n");
        }
        System.out.print(sb);
    }
   
      static boolean checkUnique(int mask,int leds,int[]arr){
          boolean[]temp=new boolean[(int)Math.pow(2, leds)+1];
          for(int i=0;i<arr.length;i++){
              int tempNum=mask&arr[i];
              if(temp[tempNum]){
                  return false;
              }
              temp[tempNum]=true;
          }
          return true;
      }
     
      static int countbits(int j){
          String temp=Integer.toBinaryString(j);
          int counter=0;
          for(int i=0;i<temp.length();i++){
              if(temp.charAt(i)=='1'){
                  counter++;
              }
          }
          return counter;
      }
}