1405. Longest Happy String

class Solution {
    public String longestDiverseString(int a, int b, int c) {
        StringBuilder sb = new StringBuilder();

        PriorityQueue<int[]> pq = new PriorityQueue<>((x, y) -> y[1] - x[1]);
        if (a > 0) pq.add(new int[]{'a', a});
        if (b > 0) pq.add(new int[]{'b', b});
        if (c > 0) pq.add(new int[]{'c', c});

        while (!pq.isEmpty()) {
            int first[] = pq.poll();
            int len = sb.length();

            if (len >= 2 && sb.charAt(len - 1) == first[0] && sb.charAt(len - 2) == first[0]) {
                if (pq.isEmpty()) continue;
                int second[] = pq.poll();
                sb.append((char) second[0]);
                second[1]--;
                if (second[1] > 0) pq.add(second);
                pq.add(first);
            } else {
                sb.append((char) first[0]);
                first[1]--;
                if (first[1] > 0) pq.add(first);
            }
        }
        return sb.toString();
    }
}