Longest Happy String LeetCode solution in C++

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class Solution {
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 public:
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  string longestDiverseString(int a, int b, int c) {
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    // using max heap
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    priority_queue<pair<int, char>> pq;
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    if (a) pq.push({a, 'a'});
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    if (b) pq.push({b, 'b'});
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    if (c) pq.push({c, 'c'});
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    string ans = "";
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    while (pq.size() > 1) {
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      pair<int, char> one = pq.top();
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      pq.pop();
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      pair<int, char> two = pq.top();
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      pq.pop();
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      if (one.first >= 2) {
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        ans += one.second;
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        ans += one.second;
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        one.first -= 2;
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      } else {
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        ans += one.second;
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        one.first -= 1;
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      }
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      if (two.first >= 2 && two.first >= one.first) {
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        ans += two.second;
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        ans += two.second;
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        two.first -= 2;
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      } else {
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        ans += two.second;
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        two.first -= 1;
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      }
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      if (one.first > 0) pq.push(one);
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      if (two.first > 0) pq.push(two);
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    }
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    if (pq.empty()) return ans;
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    if (pq.top().first >= 2) {
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      ans += pq.top().second;
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      ans += pq.top().second;
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    } else {
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      ans += pq.top().second;
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    }
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    return ans;
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  }
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};