Find shortest subarray containing all elements

Question

Suppose you have an array of numbers, and another set of numbers. You have to find the shortest subarray containing all numbers with minimal complexity.

The array ca

Answer 1

Java solution

    List paragraph = Arrays.asList("a", "c", "d", "m", "b", "a");
    Set keywords = Arrays.asList("a","b");

    Subarray result = new Subarray(-1,-1);

    Map keyWordFreq = new HashMap<>();

    int numKeywords = keywords.size();

    // slide the window to contain the all the keywords**
    // starting with [0,0]
    for (int left = 0, right = 0 ; right < paragraph.size() ; right++){

      // expand right to contain all the keywords
      String currRight = paragraph.get(right);

      if (keywords.contains(currRight)){
        keyWordFreq.put(currRight, keyWordFreq.get(currRight) == null ? 1 : keyWordFreq.get(currRight) + 1);
      }

      // loop enters when all the keywords are present in the current window
      // contract left until the all the keywords are still present
      while (keyWordFreq.size() == numKeywords){
        String currLeft = paragraph.get(left);

        if (keywords.contains(currLeft)){

          // remove from the map if its the last available so that loop exists
          if (keyWordFreq.get(currLeft).equals(1)){

            // now check if current sub array is the smallest
            if((result.start == -1 && result.end == -1) || (right - left) < (result.end - result.start)){
              result = new Subarray(left, right);
            }
            keyWordFreq.remove(currLeft);
          }else {

            // else reduce the frequcency
            keyWordFreq.put(currLeft, keyWordFreq.get(currLeft) - 1);
          }
        }
        left++;
      }

    }

    return result;
  }