Spoj Distinct Primes Problem

DistinctPrimes.java

package com.algorithms;

/**
 * @Author Mehdi Maick
 * Created on 16/09/2016.
 */

import java.time.LocalDate;
import java.util.*;
import java.io.*;

public class DistinctPrimes {
    public static void solve(FastReader fs, PrintWriter pw) {
        int t = fs.nextInt();
        while (t-- > 0) {
            int n = fs.nextInt();
            int i = 0;
            long first = 30L;
            while (i < n) {
                Set<Long> prim = PrimeFactors(first);
                if (prim.size() >= 3)
                    i++;
                if (i < n)
                    first++;
            }
            pw.println(first);
        }
    }

    public static Long factor(long n) {

        long a;
        if (n % 2 == 0)
            return 2L;
        for (a = 3; a * a <= n; a += 2) {
            if (n % a == 0)
                return a;
        }
        return n;
    }

    public static Set<Long> PrimeFactors(long n) {

        long r;
        Set<Long> ret = new HashSet<>();
        while (n > 1) {
            r = factor(n);
            ret.add(r);
            n /= r;
            if (ret.size() >= 3)
                break;
        }
        return ret;
    }

    public static void main(String[] args) throws Exception {
        FastReader fs = new FastReader(System.in);
        PrintWriter pw = new PrintWriter(new OutputStreamWriter(System.out));

        solve(fs, pw);

        fs.close();
        pw.close();
    }

    static class FastReader {

        BufferedReader reader;
        StringTokenizer st;

        FastReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream));
            st = null;
        }

        String next() {
            while (st == null || !st.hasMoreTokens()) {
                try {
                    String line = reader.readLine();
                    if (line == null) {
                        return null;
                    }
                    st = new StringTokenizer(line);
                } catch (Exception e) {
                    throw new RuntimeException();
                }
            }
            return st.nextToken();
        }

        String nextLine() {
            String s = null;
            try {
                s = reader.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return s;
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        char nextChar() {
            return next().charAt(0);
        }

        int[] nextIntArray(int n) {
            int[] arr = new int[n];
            int i = 0;
            while (i < n) {
                arr[i++] = nextInt();
            }
            return arr;
        }

        long[] nextLongArray(int n) {
            long[] arr = new long[n];
            int i = 0;
            while (i < n) {
                arr[i++] = nextLong();
            }
            return arr;
        }

        int[] nextIntArrayOneBased(int n) {
            int[] arr = new int[n + 1];
            int i = 1;
            while (i <= n) {
                arr[i++] = nextInt();
            }
            return arr;
        }

        long[] nextLongArrayOneBased(int n) {
            long[] arr = new long[n + 1];
            int i = 1;
            while (i <= n) {
                arr[i++] = nextLong();
            }
            return arr;
        }

        void close() {
            try {
                reader.close();
            } catch (IOException e) {
                System.err.println("There's been an error trying closing the reader ");
                e.printStackTrace();
            }
        }
    }


}