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

Sparse Arrays

  • 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;
    }