Submission #173155

#	Time	Username	Problem	Language	Result	Execution time	Memory
173155		TAISA_	Bridges (APIO19_bridges)	C++14	14 / 100	2807 ms	15864 KiB

bridges

#include <bits/stdc++.h>
#define all(vec) vec.begin(), vec.end()
using namespace std;
using ll = long long;
using P = pair<ll, ll>;
constexpr ll INF = (1LL << 30) - 1LL;
constexpr ll LINF = (1LL << 60) - 1LL;
constexpr ll MOD = 1e9 + 7;
template <typename T> void chmin(T &a, T b) { a = min(a, b); }
template <typename T> void chmax(T &a, T b) { a = max(a, b); }
int u[100000], v[100000], d[100000], par[50000], siz[50000];
struct UnionFind {
    void build(int n) {
        for (int i = 0; i < n; i++) {
            par[i] = i, siz[i] = 1;
        }
    }
    inline int find(int x) {
        if (par[x] == x) {
            return x;
        } else {
            return par[x] = find(par[x]);
        }
    }
    inline bool unite(int u, int v) {
        u = find(u), v = find(v);
        if (u == v)
            return false;
        if (siz[u] < siz[v])
            swap(u, v);
        par[v] = u;
        siz[u] += siz[v];
        return true;
    }
    bool same(int u, int v) { return find(u) == find(v); }
};
vector<int> G[50000];
int ok[50000];
vector<int> vv;
void dfs(int i) {
    ok[i] = 1;
    vv.emplace_back(i);
    for (auto &e : G[i]) {
        if (ok[e]) {
            continue;
        }
        dfs(e);
    }
}
int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    const int b = 800;
    int n, m;
    cin >> n >> m;
    set<pair<P, P>, greater<pair<P, P>>> es;
    for (int i = 0; i < m; i++) {
        cin >> u[i] >> v[i] >> d[i];
        --u[i];
        --v[i];
        es.insert(make_pair(P(d[i], i), P(u[i], v[i])));
    }
    int q;
    cin >> q;
    vector<int> t(q), s(q), w(q), vis(m), res(q, -1), tmp(m, -1);
    vector<pair<P, int>> qs;
    UnionFind uf;
    for (int i = 0; i < q; i++) {
        cin >> t[i] >> s[i] >> w[i];
        --s[i];
        vector<int> vs;
        if (t[i] == 1) {
            vis[s[i]] = 1;
        } else {
            qs.emplace_back(make_pair(P(w[i], s[i]), i));
        }
        if (i % b < b - 1 && i != q - 1) {
            continue;
        }
        uf.build(n);
        sort(all(qs));
        reverse(all(qs));
        int fs = (i / b) * b;
        auto it = es.begin();
        for (int j = 0; j < qs.size(); j++) {
            int ww = qs[j].first.first, st = qs[j].first.second,
                idx = qs[j].second;
            while (it != es.end() && (*it).first.first >= ww) {
                if (!vis[(*it).first.second]) {
                    uf.unite((*it).second.first, (*it).second.second);
                }
                it++;
            }
            for (int k = fs; k < idx; k++) {
                if (t[k] == 1) {
                    tmp[s[k]] = w[k];
                }
            }
            for (int k = fs; k <= i; k++) {
                if (t[k] == 1) {
                    if ((k < idx && tmp[s[k]] >= ww) ||
                        (k > idx &&
                         (tmp[s[k]] == -1 ? d[s[k]] : tmp[s[k]]) >= ww)) {
                        int uu = uf.find(u[s[k]]), vv = uf.find(v[s[k]]);
                        G[uu].emplace_back(uf.find(vv));
                        G[vv].emplace_back(uf.find(uu));
                    }
                }
            }
            for (int k = fs; k < idx; k++) {
                if (t[k] == 1) {
                    tmp[s[k]] = -1;
                }
            }
            dfs(uf.find(st));
            res[idx] = 0;
            for (auto &e : vv) {
                res[idx] += siz[uf.find(e)];
                ok[uf.find(e)] = 0;
            }
            for (int k = fs; k < idx; k++) {
                if (t[k] == 1) {
                    int uu = uf.find(u[s[k]]), vv = uf.find(v[s[k]]);
                    if (!G[uu].empty()) {
                        G[uu].clear();
                    }
                    if (!G[vv].empty()) {
                        G[vv].clear();
                    }
                }
            }
            vv.clear();
        }
        for (int j = i; j >= fs; j--) {
            if (t[j] == 1) {
                if (vis[s[j]]) {
                    es.erase(make_pair(P(d[s[j]], s[j]), P(u[s[j]], v[s[j]])));
                    d[s[j]] = w[j];
                    es.insert(make_pair(P(d[s[j]], s[j]), P(u[s[j]], v[s[j]])));
                    vis[s[j]] = 0;
                }
            }
        }
        qs.clear();
    }
    for (int i = 0; i < q; i++) {
        if (res[i] != -1) {
            cout << res[i] << endl;
        }
    }
}

Compilation message (stderr)

bridges.cpp: In function 'int main()':
bridges.cpp:85:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j = 0; j < qs.size(); j++) {
                         ~~^~~~~~~~~~~

• Subtask 1: 0 / 13
• Subtask 2: 0 / 16
• Subtask 3: 0 / 17
• Subtask 4: 14 / 14
• Subtask 5: 0 / 13
• Subtask 6: 0 / 27