mf_manoj.java

// https://www.hackerearth.com/submission/1808199/

/* IMPORTANT: class must not be public. */

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

class TestClass {
    public static void main(String args[] ) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int numOfTests = Integer.parseInt(br.readLine());
        String[] strArr;
        long lcm;
        long divisor = 1000000007;
        List<Integer> primeList = new ArrayList<Integer>();
        Set<Integer> inputSet = new HashSet<Integer>();
        List<Integer> inputList = new ArrayList<Integer>();
        List<Integer> inputList2 = new ArrayList<Integer>();
        List<Integer> indicesList = new ArrayList<Integer>();
        boolean isDivisible = false;
        int inputNum, primeNum2, num;

        primeList.add(2);
        for(int i=3; i<10000; i+=2){
            for(int primeNum : primeList){
                if(i%primeNum == 0){
                    break;
                }else if(primeNum*primeNum > i){
                    primeList.add(i);
                    break;
                }
            }
        }

        for(int i=0; i<numOfTests; i++){
            br.readLine();
            strArr = br.readLine().split(" ");
            // inputSet.clear();                             
            // inputList.clear();           BUG - these clear()s should be here, otherwise it reuses old data
            // inputList2.clear();
            // indicesList.clear();

            for(int j=0; j<strArr.length; j++){
                inputNum = Integer.parseInt(strArr[j]);
                if(inputNum != 1)
                    inputSet.add(inputNum);
            }

            inputList.addAll(inputSet);
            lcm = 1;

            for(int k=0; k<primeList.size(); k++){
                primeNum2 = primeList.get(k);
                isDivisible = false;
                for(int l=0; l<inputList.size(); l++){
                    num = inputList.get(l);
                    if(num % primeNum2 == 0){
                        isDivisible = true;
                        indicesList.add(l);
                        if(num/primeNum2 != 1)
                            inputList2.add(num/primeNum2);
                    }
                }
                if(isDivisible){
                    lcm = (lcm*primeNum2)%divisor;

                    if(inputList.size()-indicesList.size() == 0 && inputList2.size() == 0){
                        break;
                    }else{
                        for(int l=indicesList.size()-1; l>=0; l--){
                            inputList.remove((int)indicesList.get(l));
                        }
                        inputList.addAll(inputList2);
                        inputList2.clear();
                        indicesList.clear();
                        k--;
                    }
                }
                if(inputList.size() == 1){
                    lcm = (lcm*inputList.get(0))%divisor;

                    break;
                }
            }

            System.out.println(lcm);
        }
    }
}