Submission #1113218

#	Time	Username	Problem	Language	Result	Execution time	Memory
1113218		Zero_OP	절취선 (JOI14_ho_t5)	C++14	100 / 100	974 ms	77232 KiB

2014_ho_t5

#include <bits/stdc++.h>

using namespace std;

struct fenwick_tree{
    static const int offset = 1;
    vector<int> bit;
    fenwick_tree(int n) : bit(n + 1, 0) {}

    void update(int id, int val){
        id += offset;
        for(; id < (int)bit.size(); id += id & (-id)) bit[id] += val;
    }

    int query(int id){
        int sum = 0;
        id += offset;
        for(; id > 0; id -= id & (-id)) sum += bit[id];
        return sum;
    }

    void update(int l, int r, int val){
        update(l, val);
        update(r + 1, -val);
    }

    int query(int l, int r){
        int cur = query(r) - query(l - 1);
        return cur;
    }
};

struct disjoint_set{
    vector<int> lab;
    int components;
    disjoint_set(int n) : components(n), lab(n, -1) {}

    int root(int u){
        return lab[u] < 0 ? u : (lab[u] = root(lab[u]));
    }

    bool unite(int u, int v){
        u = root(u); v = root(v);
        if(u == v) return false;
        if(lab[u] > lab[v]) swap(u, v);
        lab[u] += lab[v];
        lab[v] = u;
        --components;
        return true;
    }

    int n_component(){
        return components;
    }
};

struct segment_tree_dsu{
    using info = pair<int, int>;
    vector<set<info>> st;

    segment_tree_dsu(int n) : st(n << 2) {}

    void insert(int id, int l, int r, int pos, info v){
        st[id].insert(v);
        if(l < r){
            int mid = l + r >> 1;
            if(pos <= mid) insert(id << 1, l, mid, pos, v);
            else insert(id << 1 | 1, mid + 1, r, pos, v);
        }
    }

    void erase(int id, int l, int r, int pos, info v){
        auto it = st[id].find(v);
        if(it != st[id].end()) st[id].erase(it);
        if(l < r){
            int mid = l + r >> 1;
            if(pos <= mid) erase(id << 1, l, mid, pos, v);
            else erase(id << 1 | 1, mid + 1, r, pos, v);
        }
    }

    void join_segments(int id, int l, int r, int u, int v, int match, disjoint_set& dsu){
        if(u <= l && r <= v){
            while((int)st[id].size() > 1){
                int p = st[id].begin() -> second;
                st[id].erase(st[id].begin());
                dsu.unite(match, p);
            }

            if(!st[id].empty()) dsu.unite(match, st[id].begin() -> second);
        } else{
            int mid = l + r >> 1;
            if(u <= mid) join_segments(id << 1, l, mid, u, v, match, dsu);
            if(mid < v) join_segments(id << 1 | 1, mid + 1, r, u, v, match, dsu);
        }
    }
};

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    if(fopen("task.inp", "r")){
        freopen("task.inp", "r", stdin);
        freopen("task.out", "w", stdout);
    }

    int W, H, N;
    cin >> W >> H >> N;

    vector<tuple<int, int, int, int>> cuts;
    vector<int> x, y;
    for(int i = 0; i < N; ++i){
        int a, b, c, d;
        cin >> a >> b >> c >> d;
        cuts.emplace_back(a, b, c, d);
    }

    cuts.emplace_back(0, 0, W, 0);
    cuts.emplace_back(0, 0, 0, H);
    cuts.emplace_back(W, 0, W, H);
    cuts.emplace_back(0, H, W, H);

    sort(cuts.begin(), cuts.end());
    cuts.erase(unique(cuts.begin(), cuts.end()), cuts.end());

    for(auto [a, b, c, d] : cuts){
        x.emplace_back(a);
        x.emplace_back(c);
        y.emplace_back(b);
        y.emplace_back(d);
    }

    sort(x.begin(), x.end());
    x.erase(unique(x.begin(), x.end()), x.end());

    sort(y.begin(), y.end());
    y.erase(unique(y.begin(), y.end()), y.end());

    int nx = (int)x.size(), ny = (int)y.size();
    vector<vector<pair<int, int>>> horizontal(ny), vertical(nx);

    for(auto& [a, b, c, d] : cuts){
        a = lower_bound(x.begin(), x.end(), a) - x.begin();
        c = lower_bound(x.begin(), x.end(), c) - x.begin();
        b = lower_bound(y.begin(), y.end(), b) - y.begin();
        d = lower_bound(y.begin(), y.end(), d) - y.begin();

        if(a == c){
            vertical[a].emplace_back(b, d);
        } else{
            assert(b == d);
            horizontal[b].emplace_back(a, c);
        }
    }

    struct event{
        int t, type, l, r, id;
        bool operator < (const event& o){
            return make_pair(t, type) < make_pair(o.t, o.type);
        }
    };

    vector<event> events;

    N = 0;
    for(int i = 0; i < nx; ++i){
        auto& vec = vertical[i];
        for(int j = 0; j < (int)vec.size(); ++j){
            int l, r; tie(l, r) = vec[j];
            while(j + 1 < (int)vec.size() && vec[j + 1].first <= r){
                r = max(r, vec[j + 1].second);
                ++j;
            }

            events.push_back({i, 1, l, r, N++});
        }
    }

    for(int i = 0; i < ny; ++i){
        auto& vec = horizontal[i];
        for(int j = 0; j < (int)vec.size(); ++j){
            int l, r; tie(l, r) = vec[j];
            while(j + 1 < (int)vec.size() && vec[j + 1].first <= r){
                r = max(r, vec[j + 1].second);
                ++j;
            }

            events.push_back({l, 0, i, r, N});
            events.push_back({r, 2, i, r, N});
            ++N;
        }
    }

    sort(events.begin(), events.end());
    long long n_intersection = 0;

    fenwick_tree ft(ny);
    disjoint_set dsu(N);
    segment_tree_dsu segtree(ny);

    for(auto [t, type, l, r, id] : events){
        if(type == 0){
            segtree.insert(1, 0, ny - 1, l, make_pair(r, id));
            ft.update(l, +1);
        } else if(type == 1){
            segtree.join_segments(1, 0, ny - 1, l, r, id, dsu);
            n_intersection += ft.query(l, r);
        } else{
            segtree.erase(1, 0, ny - 1, l, make_pair(r, id));
            ft.update(l, -1);
        }
    }

    long long V = n_intersection;
    long long E = N;
    long long C = dsu.n_component();

    cout << V - E + C << '\n';

    return 0;
}

Compilation message (stderr)

2014_ho_t5.cpp: In constructor 'disjoint_set::disjoint_set(int)':
2014_ho_t5.cpp:35:9: warning: 'disjoint_set::components' will be initialized after [-Wreorder]
   35 |     int components;
      |         ^~~~~~~~~~
2014_ho_t5.cpp:34:17: warning:   'std::vector<int> disjoint_set::lab' [-Wreorder]
   34 |     vector<int> lab;
      |                 ^~~
2014_ho_t5.cpp:36:5: warning:   when initialized here [-Wreorder]
   36 |     disjoint_set(int n) : components(n), lab(n, -1) {}
      |     ^~~~~~~~~~~~
2014_ho_t5.cpp: In member function 'void segment_tree_dsu::insert(int, int, int, int, segment_tree_dsu::info)':
2014_ho_t5.cpp:66:25: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   66 |             int mid = l + r >> 1;
      |                       ~~^~~
2014_ho_t5.cpp: In member function 'void segment_tree_dsu::erase(int, int, int, int, segment_tree_dsu::info)':
2014_ho_t5.cpp:76:25: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   76 |             int mid = l + r >> 1;
      |                       ~~^~~
2014_ho_t5.cpp: In member function 'void segment_tree_dsu::join_segments(int, int, int, int, int, int, disjoint_set&)':
2014_ho_t5.cpp:92:25: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   92 |             int mid = l + r >> 1;
      |                       ~~^~~
2014_ho_t5.cpp: In function 'int main()':
2014_ho_t5.cpp:127:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  127 |     for(auto [a, b, c, d] : cuts){
      |              ^
2014_ho_t5.cpp:143:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  143 |     for(auto& [a, b, c, d] : cuts){
      |               ^
2014_ho_t5.cpp:202:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  202 |     for(auto [t, type, l, r, id] : events){
      |              ^
2014_ho_t5.cpp:104:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  104 |         freopen("task.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
2014_ho_t5.cpp:105:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |         freopen("task.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 20 / 20
• Subtask 4: 20 / 20
• Subtask 5: 50 / 50