Submission #706519

#	Time	Username	Problem	Language	Result	Execution time	Memory
706519		Valera_Grinenko	Railway (BOI17_railway)	C++17	0 / 100	88 ms	27268 KiB

railway

//#pragma GCC optimize("Ofast", "unroll-loops")
//#pragma GCC target("sse", "sse2", "sse3", "ssse3", "sse4")

#ifdef __APPLE__

#include <iostream>
#include <cmath>
#include <algorithm>
#include <cstdio>
#include <cstdint>
#include <cstring>
#include <string>
#include <cstdlib>
#include <vector>
#include <bitset>
#include <map>
#include <queue>
#include <ctime>
#include <stack>
#include <set>
#include <list>
#include <random>
#include <deque>
#include <functional>
#include <iomanip>
#include <sstream>
#include <fstream>
#include <complex>
#include <numeric>
#include <immintrin.h>
#include <cassert>
#include <array>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <thread>

#else
#include <bits/stdc++.h>
#endif

#define all(a) a.begin(),a.end()
#define len(a) (int)(a.size())
#define mp make_pair
#define pb push_back
#define fir first
#define sec second
#define fi first
#define se second

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
typedef long double ld;

template<typename T>
bool umin(T &a, T b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}

template<typename T>
bool umax(T &a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

#if __APPLE__
#define D for (bool _FLAG = true; _FLAG; _FLAG = false)
#define LOG(...) print(#__VA_ARGS__" ::", __VA_ARGS__) << endl

template<class ...Ts>
auto &print(Ts ...ts) { return ((cerr << ts << " "), ...); }

#else
#define D while (false)
#define LOG(...)
#endif

//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

struct stsum_add {
    static const int Nst = 1e5 + 42;
    ll st[Nst * 4];
    ll lazy[Nst * 4];
    int tree_l[Nst * 4], tree_r[Nst * 4];
    ll seg_len[Nst * 4];

    void push(int v) {
        if (!lazy[v]) return;
        st[(v << 1)] += lazy[v] * seg_len[(v << 1)];
        st[(v << 1) + 1] += lazy[v] * seg_len[(v << 1) + 1];
        lazy[(v << 1)] += lazy[v];
        lazy[(v << 1) + 1] += lazy[v];
        lazy[v] = 0;
    }

    void init(int v = 1, int tl = 0, int tr = Nst - 1) {
        tree_l[v] = tl;
        tree_r[v] = tr;
        seg_len[v] = (tr - tl + 1);
        if (tl == tr) {
            st[v] = 0;
            lazy[v] = 0;
        }
        else {
            int tm = (tl + tr) / 2;
            init((v << 1), tl, tm);
            init((v << 1) + 1, tm + 1, tr);
            st[v] = 0;
            lazy[v] = 0;
        }
    }

    ll get(int l, int r, int v = 1, int tl = 0, int tr = Nst - 1) {
        if (l > r) return 0;
        if (l <= tl && tr <= r) return st[v];
        push(v);
        int tm = ((tl + tr) >> 1);
        return (get(l, min(r, tm), (v << 1), tl, tm) + get(max(l, tm + 1), r, (v << 1) + 1, tm + 1, tr));
    }

    void upd(int l, int r, ll delta, int v = 1, int tl = 0, int tr = Nst - 1) {
        if (l > r) return;
        if (l == tl && r == tr) {
            st[v] += delta * seg_len[v];
            lazy[v] += delta;
        } else {
            push(v);
            int tm = ((tl + tr) >> 1);
            upd(l, min(r, tm), delta, (v << 1), tl, tm);
            upd(max(l, tm + 1), r, delta, (v << 1) + 1, tm + 1, tr);
            st[v] = (st[(v << 1)] + st[(v << 1) + 1]);
        }
    }
};

stsum_add st;

struct HLD {
    static const int maxN = 1e5 + 42;
    vector<int> g[maxN];
    int head[maxN] = {}, parent[maxN] = {}, depth[maxN] = {}, subt[maxN] = {};
    int pos[maxN] = {};
    int curpos = 0;
    bool VALS_IN_EDGES = 0;

    void init(int root) {
        parent[root] = depth[root] = curpos = 0;
        predfs(root);
        head[root] = root;
        dfsHLD(root);
    }

    void add_edge(int a, int b) {
        g[a].pb(b);
        g[b].pb(a);
    }

    void predfs(int v) {
        subt[v] = 1;
        for (auto &to: g[v]) {
            parent[to] = v;
            depth[to] = depth[v] + 1;
            g[to].erase(find(all(g[to]), v));
            predfs(to);
            subt[v] += subt[to];
            if (subt[to] > subt[g[v][0]]) swap(g[v][0], to);
        }
    }

    void dfsHLD(int v) {
        pos[v] = curpos++;
        for (auto &to: g[v]) {
            head[to] = (to == g[v][0] ? head[v] : to);
            dfsHLD(to);
        }
    }

    int lca(int a, int b) {
        for (; head[a] != head[b]; b = parent[head[b]]) {
            if (depth[head[a]] > depth[head[b]]) swap(a, b);
        }
        if (depth[a] > depth[b]) swap(a, b);
        return a;
    }

    int query_path(int a, int b) {
        int res = 0;
        for (; head[a] != head[b]; b = parent[head[b]]) {
            if (depth[head[a]] > depth[head[b]]) swap(a, b);
            res += st.get(pos[head[b]], pos[b]);
        }
        if (depth[a] > depth[b]) swap(a, b);
        res += st.get(pos[a] + VALS_IN_EDGES, pos[b]);
        return res;
    }

    void upd_path(int a, int b, int val) {
        for (; head[a] != head[b]; b = parent[head[b]]) {
            if (depth[head[a]] > depth[head[b]]) swap(a, b);
            st.upd(pos[head[b]], pos[b], val);
        }
        if (depth[a] > depth[b]) swap(a, b);
        st.upd(pos[a] + VALS_IN_EDGES, pos[b], val);
    }

    void upd_subtree(int v, int val) {
        st.upd(pos[v] + VALS_IN_EDGES, pos[v] + subt[v] - 1, val);
    }
};

void solve() {
    int n, m, k;
    cin >> n >> m >> k;
    vector<pair<int, int> > edg(n - 1);
    HLD hld; hld.VALS_IN_EDGES = true; st.init();
    for(int i = 0; i + 1 < n; i++) {
        cin >> edg[i].fi >> edg[i].se;
        edg[i].fi--; edg[i].se--;
        hld.add_edge(edg[i].fi, edg[i].se);
    }
    hld.init(0);
    for(int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b; a--; b--;
        hld.upd_path(a, b, 1);
    }
    vector<int> ans;
    for(int i = 0; i + 1 < n; i++) {
        if(hld.query_path(edg[i].fi, edg[i].se) >= k) ans.pb(i + 1);
    }
    cout << len(ans) << '\n';
    for(auto& x : ans) cout << x << ' ';
}

signed main() {
//   freopen("input.txt", "r", stdin);
//   freopen("output.txt", "w", stdout);

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int t = 1;

    //cin >> t;

    while (t--) solve();

}

/*
KIVI
*/

• Subtask 1: 0 / 8
• Subtask 2: 0 / 15
• Subtask 3: 0 / 7
• Subtask 4: 0 / 29
• Subtask 5: 0 / 16
• Subtask 6: 0 / 25