1405.cpp

class Solution {
public:
    string longestDiverseString(int a, int b, int c) {
        priority_queue<pair<int, char>> pq;
        if (a != 0) pq.push({a, 'a'});
        if (b != 0) pq.push({b, 'b'});
        if (c != 0) pq.push({c, 'c'});

        string res;
        while (!pq.empty()) {
            if (pq.size() == 1) {
                int k = min(2, pq.top().first);
                for (int i = 0; i < k; ++i) res.push_back(pq.top().second);
                return res;
            }
            auto x = pq.top();
            pq.pop();
            auto y = pq.top();
            pq.pop();
            int k = min(2, x.first - y.first);
            for (int i = 0; i < k; ++i) res.push_back(x.second);
            res.push_back(y.second);

            x.first -= k;
            y.first -= 1;
            if (x.first > 0) pq.push(x);
            if (y.first > 0) pq.push(y);
        }
        return res;
    }
};