Untitled

String[] solution(String[] chain, String[] elements) {
        // To store the count of each golden element needed.
        Map<String, Integer> goldenElementCount = new HashMap<>();
        for (String element : elements) {
            goldenElementCount.put(element, goldenElementCount.getOrDefault(element, 0) + 1);
        }
        
        // Variables to keep track of the sliding window.
        int left = 0, right = 0;
        int minLength = Integer.MAX_VALUE;
        int minLeft = 0, minRight = 0;
        int totalElementsNeeded = goldenElementCount.size();
        int currentMatchedElements = 0;
        
        Map<String, Integer> windowElementCount = new HashMap<>();
        
        // Start the sliding window.
        while (right < chain.length) {
            // Add the right element to the window.
            String rightElement = chain[right];
            windowElementCount.put(rightElement, windowElementCount.getOrDefault(rightElement, 0) + 1);
            
            // Check if we have matched the count of a golden element.
            if (goldenElementCount.containsKey(rightElement) && 
                windowElementCount.get(rightElement).equals(goldenElementCount.get(rightElement))) {
                currentMatchedElements++;
            }
            
            // Try to shrink the window till it contains all elements.
            while (currentMatchedElements == totalElementsNeeded && left <= right) {
                if (right - left + 1 < minLength) {
                    minLength = right - left + 1;
                    minLeft = left;
                    minRight = right;
                }
                
                // Remove the left element from the window.
                String leftElement = chain[left];
                windowElementCount.put(leftElement, windowElementCount.get(leftElement) - 1);
                
                // Check if we have removed a matched golden element.
                if (goldenElementCount.containsKey(leftElement) && 
                    windowElementCount.get(leftElement) < goldenElementCount.get(leftElement)) {
                    currentMatchedElements--;
                }
                
                left++;
            }
            
            right++;
        }
        
        // If no such sub-chain exists that contains all elements.
        if (minLength == Integer.MAX_VALUE) {
            return new String[0];
        }
        
        // Return the smallest sub-chain.
        String[] result = new String[minLength];
        System.arraycopy(chain, minLeft, result, 0, minLength);
        return result;
    }