Connect Ropes

• Time : $O(nlogn)$
• Space : $O(n)$

int Solution::solve(vector<int> &A) {
    int res = 0;
    priority_queue<int, vector<int>, greater<int>> q;
    for(auto a : A) q.push(a);
    while(q.size() > 1) {
        auto a = q.top(); q.pop();
        auto b = q.top(); q.pop();
        res += a + b;
        q.push(a + b);
    }
    return res;
}