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  1. Practice
  2. Data Structures
  3. Arrays
  4. Sparse Arrays
  5. Discussions

Sparse Arrays

  • ChrisAyad + 2 comments

    Thank you for your helpful comment. I can't find the imports. Actually the problem is with the parsing of the input as mentioned previously. Even a simple loop had trouble. It seems "hit and miss" with this website.

    • raggzy + 0 comments

      Just in case, here is version with boilerplate. Java8, copypaste, ..., profit!

      import java.io.*;
import java.util.*;
import java.util.stream.*;

public class Solution {
    // the code from above
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        List<String> strings = IntStream.range(0, in.nextInt()).mapToObj(i -> in.next()).collect(Collectors.toList());
        IntStream.range(0, in.nextInt()).mapToObj(i -> in.next()).mapToLong(q -> strings.stream().filter(q::equals).count()).forEach(System.out::println);
    }
    //
}
    • pandaman + 2 comments

      why so negative? this isn't a website that offers solutions to problems, but a place for people to learn.

      • gabi_nofx + 1 comment

        Using stream is inefficient

        • chesschingis + 1 comment

          Hi!

          Speaking of learning concepts, if I wanted to use Maps without Stream, what are the steps I would use for that? Specifically, from the half-dozen websites I researched, but it seems like I will have to manually place strings into the maps; is this correct?

          Will operation time be O(n + q + hash_constant), then?

          This is one of my first posts; sorry if this is a stupid question/formatted badly.

          Thanks in advance.

          • prathameshbagek1 + 0 comments

            This is my code in Java 8, I've presented the snippet of the concerned method, hope this helps. Here you go..

            static int[] matchingStrings(String[] strings, String[] queries) {
        Map<String, Integer> map = new HashMap<>();
        for (String string : strings) {
            if (!map.containsKey(string))
                map.put(string, 1);
            else {
                int count = map.get(string);
                map.put(string, ++count);
            }
        }
        int[] array = new int[queries.length];
        int count = 0;
        for (String string : queries) {
            if (map.containsKey(string))
                array[count++] = map.get(string);
            else
                count++;
        }
        return array;
    }
      • nishantt50 + 0 comments

        than why are you reading comments?