Submission #738020

#	Time	Username	Problem	Language	Result	Execution time	Memory
738020		GrindMachine	Valley (BOI19_valley)	C++17	0 / 100	121 ms	22848 KiB

valley

// Om Namah Shivaya

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a, b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a, b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*



*/

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

struct DSU {
    vector<int> par, rankk, siz;
    vector<array<int, 3>> history;

    DSU() {

    }

    DSU(int n) {
        init(n);
    }

    void init(int n) {
        par = vector<int>(n + 1);
        rankk = vector<int>(n + 1);
        siz = vector<int>(n + 1);
        rep(i, n + 1) create(i);
    }

    void create(int u) {
        par[u] = u;
        rankk[u] = 0;
        siz[u] = 1;
    }

    int find(int u) {
        if (u == par[u]) return u;
        else return par[u] = find(par[u]);
    }

    bool same(int u, int v) {
        return find(u) == find(v);
    }

    void merge(int u, int v) {
        u = find(u), v = find(v);
        if (u == v) return;

        history.pb({u, par[u], rankk[u]});
        history.pb({v, par[v], rankk[v]});

        if (rankk[u] == rankk[v]) rankk[u]++;
        if (rankk[u] < rankk[v]) swap(u, v);

        par[v] = u;
        siz[u] += siz[v];
    }

    void rollback(ll times) {
        times *= 2;
        while (times--) {
            if (history.empty()) {
                exit(108);
            }

            auto [u, pa, rnk] = history.back();
            history.pop_back();
            par[u] = pa;
            rankk[u] = rnk;
        }
    }
};

vector<pll> adj[N];
vector<array<ll, 3>> edges(N);
vector<ll> conn(N);
vector<pll> queries_here[N];
DSU dsu;
ll des;

void go(ll l, ll r) {
    if (l == r) {
        for (auto [u, qid] : queries_here[l]) {
            conn[qid] = dsu.same(u, des);
        }

        return;
    }

    ll mid = (l + r) >> 1;

    // remove edge is in range [l,mid]
    for (int i = mid + 1; i <= r; ++i) {
        auto [u, v, w] = edges[i];
        dsu.merge(u, v);
    }

    go(l, mid);
    dsu.rollback(r - mid);

    // removed edge is in range [mid+1,r]
    for (int i = l; i <= mid; ++i) {
        auto [u, v, w] = edges[i];
        dsu.merge(u, v);
    }

    go(mid + 1, r);
    dsu.rollback(mid - l + 1);
}

void solve(int test_case)
{
    ll n, s, q; cin >> n >> s >> q;
    cin >> des;

    rep1(i, n - 1) {
        ll u, v, w; cin >> u >> v >> w;
        edges[i] = {u, v, w};
        adj[u].pb({v, w}), adj[v].pb({u, w});
    }

    vector<ll> spl(s + 5);
    rep1(i, s) cin >> spl[i];

    dsu = DSU(n + 5);
    vector<pll> queries(q + 5);

    rep1(i, q) {
        ll id, u; cin >> id >> u;
        queries[i] = {u, id};
        queries_here[id].pb({u, i});
    }

    go(1, n - 1);

    rep1(i, q) {
        if (conn[i]) {
            cout << "escaped" << endl;
        }
        else {
            cout << 0 << endl;
        }
    }
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

• Subtask 1: 0 / 9
• Subtask 2: 0 / 27
• Subtask 3: 0 / 23
• Subtask 4: 0 / 41