map

// map<A, B>
template<typename A, typename B> 
ostream &operator <<(ostream &os, const map<A, B> &M) {
    os << ‘[‘; 
    for (auto it = M.begin(); it != M.end(); ++it) {
        os << ‘(‘ << it -> first << ": " << it -> second << ‘)‘;
        ++it;
        if (it != M.end()) {
            os << ", "; 
        }
        --it;
    }
    os << ‘]‘;
    return os;
}

// unordered_map<A, B>
template<typename A, typename B> 
ostream &operator <<(ostream &os, const unordered_map<A, B> &M) {
    os << ‘[‘; 
    for (auto it = M.begin(); it != M.end(); ++it) {
        os << ‘(‘ << it -> first << ": " << it -> second << ‘)‘;
        ++it;
        if (it != M.end()) {
            os << ", "; 
        }
        --it;
    }
    os << ‘]‘;
    return os;
}

set

// set<T>
template<typename T> 
ostream &operator <<(ostream &os, const set<T> &S) {
    os << ‘{‘;
    for (auto it = S.begin(); it != S.end(); ++it) {
        os << *it;
        if (++it != S.end()) {
            os << ", "; 
        }
        --it;
    }
    os << ‘}‘;
    return os;
}

// unordered_set<T>
template<typename T> 
ostream &operator <<(ostream &os, const unordered_set<T> &S) {
    os << ‘{‘;
    for (auto it = S.begin(); it != S.end(); ++it) {
        os << *it;
        if (++it != S.end()) {
            os << ", "; 
        }
        --it;
    }
    os << ‘}‘;
    return os;
}

// multiset<T> 
template<typename T> 
ostream &operator <<(ostream &os, const multiset<T> &S) {
    os << ‘{‘;
    for (auto it = S.begin(); it != S.end(); ++it) {
        os << *it;
        if (++it != S.end()) {
            os << ", "; 
        }
        --it;
    }
    os << ‘}‘;
    return os;
}

vector

// vector<T>
template<typename T> 
ostream &operator <<(ostream &os, const vector<T> &V) {
    os << ‘[‘;
    for (int i = 0; i < V.size(); ++i) {
        os << V[i];
        if ((i + 1) ^ V.size()) 
            os << ", ";
    }
    os << ‘]‘;
    return os;
}

// vector<pair<A, B>> 
template<typename A, typename B> 
ostream &operator <<(ostream &os, const vector<pair<A, B>> &V) {
    os << ‘[‘;
    for (int i = 0; i < V.size(); ++i) {
        os << ‘(‘ << V[i].first << ", " << V[i].second << ‘)‘;
        if ((i + 1) ^ V.size()) 
            os << ", ";
    }
    os << ‘]‘;
    return os;
}

stack

template<typename T>
ostream &operator <<(ostream &os, stack<T> S) {
    os << "\n- - - TOP - - -\n";
    while (!S.empty()) {
        os << S.top();
        S.pop();
        os << ‘\n‘;
    }
    os << "- - - BOTTOM - - -\n";
    return os;
}

queue

// priority_queue<T>
template<typename T>
ostream &operator <<(ostream &os, priority_queue<T> Q) {
    os << ‘[‘;
    while (!Q.empty()) {
        os << Q.top(); 
        Q.pop();
        if (!Q.empty()) {
            os << ", ";
        }
    }
    os << ‘]‘;
    return os;
}

template<typename T>
ostream &operator <<(ostream &os, priority_queue<T, vector<T>, greater<T>> Q) {
    os << ‘[‘;
    while (!Q.empty()) {
        os << Q.top(); 
        Q.pop();
        if (!Q.empty()) {
            os << ", ";
        }
    }
    os << ‘]‘;
    return os;
}

// queue<T>
template<typename T>
ostream &operator <<(ostream &os, queue<T> Q) {
    os << ‘[‘;
    while (!Q.empty()) {
        os << Q.front(); 
        Q.pop();
        if (!Q.empty()) {
            os << ", ";
        }
    }
    os << ‘]‘;
    return os;
}

// deque<T>
template<typename T>
ostream &operator <<(ostream &os, deque<T> Q) {
    os << ‘[‘;
    while (!Q.empty()) {
        os << Q.front(); 
        Q.pop_front();
        if (!Q.empty()) {
            os << ", ";
        }
    }
    os << ‘]‘;
    return os;
}

debug