Codeforces-solutions/Codeforces Round 147 (Div. 2)/E. Build String.cpp

/* Problem URL: https://codeforces.com/problemset/problem/237/E */

#include <bits/stdc++.h>

using namespace std;

#define V vector

#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)

#define rep(i, lim) for (size_t i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (size_t i = s; i < (lim); i++)

#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()

using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;

using ll = long long;

using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;

template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
    os << vec[0];
    for (size_t i = 1; i < vec.size(); i++) {
        os << ' ' << vec[i];
    }
    os << '\n';
    return os;
}

template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
    for (auto &i : vec) {
        is >> i;
    }
    return is;
}

template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
    for (auto &i : vec) {
        os << i[0];
        for (size_t j = 1; j < i.size(); j++) {
            os << ' ' << i[j];
        }
        os << '\n';
    }
    return os;
}

template<class v>
auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
    for (auto &i : vec) {
        for (auto &j : i) {
            is >> j;
        }
    }
    return is;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    string a;
    cin >> a;

    vi acount(26, 0);
    int tmp = 0;
    repv(i, a) {
        if (acount[i - 'a'] == 0) {
            tmp++;
        }
        acount[i - 'a']++;
    }

    int n;
    cin >> n;
    size_t size = n + 2 + tmp;

    vector<vector<int>> graph(size);
    vector<vector<int>> cost(size, vector<int>(size, 0));
    vector<vector<int>> capacity(size, vector<int>(size, 0));

    auto addedge = [&](int u, int v, int c, int p){
        graph[u].push_back(v);
        graph[v].push_back(u);
        cost[u][v] = c;
        cost[v][u] = -c;
        capacity[u][v] = p;
    };

    vi act(26, -1);
    int v = 1;
    rep(i, 26) {
	    if (acount[i] > 0) {
	        act[i] = v;
	        addedge(v, size - 1, 0, acount[i]);
	        v++;
	    }
    }

    int start = v;

    for (size_t i = 1; i <= n; i++) {
        string b;
        int lol;
        cin >> b >> lol;

        vi bcount(26, 0);
        repv(j, b) {
            bcount[j - 'a']++;
        }

        rep(j, 26) {
            if (bcount[j] > 0 && acount[j] > 0) {
                addedge(v, act[j], i, bcount[j]);
            }
        }

        addedge(0, v, 0, lol);

        v++;
    }

    int inf = INT32_MAX >> 1;
    vector<int> p(size, inf);
    vector<int> d(size, -1);

    int s = 0;
    int t = size - 1;

    auto bfs = [&](){
        d[s] = 0;
        vector<bool> inq(size, false);
        queue<int> q;
        q.push(s);

        while (!q.empty()) {
            int u = q.front();
            q.pop();
            inq[u] = false;

            for (auto v : graph[u]) {
                if (capacity[u][v] > 0 && d[v] > d[u] + cost[u][v]) {
                    d[v] = d[u] + cost[u][v];
                    p[v] = u;
                    if (!inq[v]) {
                        inq[v] = true;
                        q.push(v);
                    }
                }
            }
        }

        return d[t] != inf;
    };

    vector<bool> vis(n * 2 + 2, false);


    int flow = 0;
    int c = 0;
    while (flow < a.size()) {
        fill(d.begin(), d.end(), inf);
        fill(p.begin(), p.end(), -1);
        if (!bfs()) {
            break;
        }

        int f = inf;
        int cur = t;
        while (cur != s) {
            f = min(f, capacity[p[cur]][cur]);
            cur = p[cur];
        }

        flow += f;
        c += f * d[t];
        cur = t;
        while (cur != s) {
            capacity[p[cur]][cur] -= f;
            capacity[cur][p[cur]] += f;
            cur = p[cur];
        }
    }

    if (flow < a.size()) {
        cout << "-1\n";
        return 0;
    }

    cout << c << '\n';

}