Submission #335447

#	Time	Username	Problem	Language	Result	Execution time	Memory
335447		12tqian	Valley (BOI19_valley)	C++17	100 / 100	1629 ms	61280 KiB

valley

#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <iostream>
#include <iomanip>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <vector>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str;

typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<db, db> pd;

typedef vector<int> vi;
typedef vector<bool> vb;
typedef vector<ll> vl;
typedef vector<db> vd;
typedef vector<str> vs;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<pd> vpd;

#define mp make_pair
#define f first
#define s second
#define sz(x) (int) (x).size()
#define all(x) begin(x), end(x)
#define rall(x) (x).rbegin(), (x).rend()
#define sor(x) sort(all(x))
#define rsz resize
#define resz resize
#define ins insert
#define ft front()
#define bk back()
#define pf push_front
#define pb push_back
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound

#define f1r(i, a, b) for(int i = (a); i < (b); ++i)
#define f0r(i, a) f1r(i, 0, a)
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define F0R(i, a) FOR(i,0,a)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); --i)
#define R0F(i, a) ROF(i, 0, a)
#define trav(a, x) for (auto& a : x)

mt19937 rng((uint32_t) chrono::steady_clock::now().time_since_epoch().count());

template<class T> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
template<class T> using V = vector<T>;

#ifdef LOCAL
#define dbg(...) debug(#__VA_ARGS__, __VA_ARGS__);
#else
#define dbg(...) 17;
#endif

template<typename T, typename S> ostream& operator << (ostream &os, const pair<T, S> &p) { return os << "(" << p.first << ", " << p.second << ")"; }
template<typename C, typename T = decay<decltype(*begin(declval<C>()))>, typename enable_if<!is_same<C, string>::value>::type* = nullptr>
ostream& operator << (ostream &os, const C &c) { bool f = true; os << "{"; for (const auto &x : c) { if (!f) os << ", "; f = false; os << x; } return os << "}"; }
template<typename T> void debug(string s, T x) { cerr << s << " = " << x << "\n"; }
template<typename T, typename... Args> void debug(string s, T x, Args... args) { cerr << s.substr(0, s.find(',')) << " = " << x << " | "; debug(s.substr(s.find(',') + 2), args...); }

constexpr int pct(int x) { return __builtin_popcount(x); }
constexpr int bits(int x) { return 31 - __builtin_clz(x); } // floor(log2(x))

namespace input {
    template<class T> void re(complex<T>& x);
    template<class T1, class T2> void re(pair<T1, T2>& p);
    template<class T> void re(vector<T>& a);
    template<class T, int SZ> void re(array<T, SZ>& a);
    template<class T> void re(T& x) { cin >> x; }
    void re(double& x) { string t; re(t); x = stod(t); }
    void re(ld& x) { string t; re(t); x = stold(t); }
    template<class T, class... Ts> void re(T& t, Ts&... ts) {
        re(t); re(ts...); }
    template<class T> void re(complex<T>& x) { T a, b; re(a, b); x = cd(a, b); }
    template<class T1, class T2> void re(pair<T1, T2>& p) { re(p.f, p.s); }
    template<class T> void re(vector<T>& a) { F0R(i, sz(a)) re(a[i]); }
    template<class T, int SZ> void re(array<T, SZ>& a) { F0R(i, SZ) re(a[i]); }
}

using namespace input;

namespace output {
    void pr(int x) { cout << x; }
    void pr(long x) { cout << x; }
    void pr(ll x) { cout << x; }
    void pr(unsigned x) { cout << x; }
    void pr(unsigned long x) { cout << x; }
    void pr(unsigned long long x) { cout << x; }
    void pr(float x) { cout << x; }
    void pr(double x) { cout << x; }
    void pr(ld x) { cout << x; }
    void pr(char x) { cout << x; }
    void pr(const char* x) { cout << x; }
    void pr(const string& x) { cout << x; }
    void pr(bool x) { pr(x ? "true" : "false"); }
    template<class T> void pr(const complex<T>& x) { cout << x; }
    template<class T1, class T2> void pr(const pair<T1, T2>& x);
    template<class T> void pr(const T& x);
    template<class T, class... Ts> void pr(const T& t, const Ts&... ts) {
        pr(t); pr(ts...); }
    template<class T1, class T2> void pr(const pair<T1,T2>& x) {
        pr("{", x.f, ", ", x.s, "}"); }
    template<class T> void pr(const T& x) {
        pr("{"); // const iterator needed for vector<bool>
        bool fst = 1; for (const auto& a: x) pr(!fst ? ", " : "", a), fst = 0;
        pr("}"); }
    void ps() { pr("\n"); } // print w/ spaces
    template<class T, class... Ts> void ps(const T& t, const Ts&... ts) {
        pr(t); if (sizeof...(ts)) pr(" "); ps(ts...); }
    void pc() { pr("]\n"); } // debug w/ commas
    template<class T, class... Ts> void pc(const T& t, const Ts&... ts) {
        pr(t); if (sizeof...(ts)) pr(", "); pc(ts...); }
}

using namespace output;

namespace io {
    void setIn(string s) { freopen(s.c_str(), "r", stdin); }
    void setOut(string s) { freopen(s.c_str(), "w", stdout); }
    void setIO(string s = "") {
        cin.sync_with_stdio(0); cin.tie(0);
        if (sz(s)) { setIn(s + ".in"), setOut(s + ".out"); }
    }
}

using namespace io;

const int MOD = 1e9 + 7; // 998244353;
const ld PI = acos((ld) -1);

typedef std::decay <decltype(MOD)>::type mod_t;
struct mi {
    mod_t val;
    explicit operator mod_t() const { return val; }
    mi() { val = 0; }
    mi(const long long& v) {
        val = (-MOD <= v && v <= MOD) ? v : v % MOD;
        if (val < 0) val += MOD; }
    friend std::istream& operator >> (std::istream& in, mi& a) {
        long long x; std::cin >> x; a = mi(x); return in; }
    friend std::ostream& operator << (std::ostream& os, const mi& a) { return os << a.val; }
    friend bool operator == (const mi& a, const mi& b) { return a.val == b.val; }
    friend bool operator != (const mi& a, const mi& b) { return !(a == b); }
    friend bool operator < (const mi& a, const mi& b) { return a.val < b.val; }
    friend bool operator > (const mi& a, const mi& b) { return a.val > b.val; }
    friend bool operator <= (const mi& a, const mi& b) { return a.val <= b.val; }
    friend bool operator >= (const mi& a, const mi& b) { return a.val >= b.val; }
    mi operator - () const { return mi(-val); }
    mi& operator += (const mi& m) {
        if ((val += m.val) >= MOD) val -= MOD;
        return *this; }
    mi& operator -= (const mi& m) {
        if ((val -= m.val) < 0) val += MOD;
        return *this; }
    mi& operator *= (const mi& m) { val = (long long) val * m.val % MOD;
        return *this; }
    friend mi pow(mi a, long long p) {
        mi ans = 1; assert(p >= 0);
        for (; p; p /= 2, a *= a) if (p & 1) ans *= a;
        return ans; }
    friend mi inv(const mi& a) { assert(a != 0); return pow(a, MOD - 2); }
    mi& operator /= (const mi& m) { return (*this) *= inv(m); }
    friend mi operator + (mi a, const mi& b) { return a += b; }
    friend mi operator - (mi a, const mi& b) { return a -= b; }
    friend mi operator * (mi a, const mi& b) { return a *= b; }
    friend mi operator / (mi a, const mi& b) { return a /= b; }
};
typedef pair<mi, mi> pmi;
typedef vector<mi> vmi;
typedef vector<pmi> vpmi;

const ll INF = 1e16;
const ll CUT = 1e14 + 1;

template <class T> struct LazySeg {
    std::vector<T> mn, lazy;
    int sz;
    void init(int sz_) {
        sz = 1;
        while (sz < sz_) sz *= 2;
        mn.assign(2 * sz, 0);
        lazy.assign(2 * sz, 0);
    }
    void push(int ind, int L, int R) {
        mn[ind] += lazy[ind];
        if (L != R) {
            lazy[2 * ind] += lazy[ind];
            lazy[2 * ind + 1] += lazy[ind];
        }
        lazy[ind] = 0;
    }
    void pull(int ind) {
        mn[ind] = min(mn[2 * ind], mn[2 * ind + 1]);
    }
    void build() {
        for (int i = sz - 1; i >= 1; i--) {
            pull(i);
        }
    }
    void upd(int lo, int hi, T inc, int ind = 1, int L = 0, int R = -1) {
        if (R == -1) R += sz;
        push(ind, L, R);
        if (hi < L || R < lo) return ;
        if (lo <= L && R <= hi) {
            lazy[ind] = inc;
            push(ind, L, R);
            return;
        }
        int M = (L + R) / 2;
        upd(lo, hi, inc, 2 * ind, L, M);
        upd(lo, hi, inc, 2 * ind + 1, M + 1, R);
        pull(ind);
    }
    T qmin(int lo, int hi, int ind = 1, int L = 0, int R = -1) {
        if (R == -1) R += sz;
        push(ind, L, R);
        if (lo > R || L > hi) return INF;
        if (lo <= L && R <= hi) return mn[ind];
        int M = (L + R) / 2;
        return min(qmin(lo, hi, 2 * ind, L, M), qmin(lo, hi, 2 * ind + 1, M + 1, R));
    }
};
struct LCAJump {
    int n;
    std::vector<std::vector<int>> par;
    std::vector<std::vector<int>> adj;
    std::vector<int> depth;
    void init(int _n) {
        n = _n;
        int d = 1;
        while ((1 << d) < n) d++;
        par.assign(d, std::vector<int>(n));
        adj.resize(n);
        depth.resize(n);
    }
    void ae(int x, int y) {
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    void gen(int root = 0) {
        par[0][root] = root;
        dfs(root);
    }
    void dfs(int src = 0) {
        for (int i = 1; i < (int) par.size(); i++) {
            par[i][src] = par[i - 1][par[i - 1][src]];
        }
        for (int nxt: adj[src]) {
            if (nxt == par[0][src]) continue;
            depth[nxt] = depth[par[0][nxt] = src] + 1;
            dfs(nxt);
        }
    }
    int jump(int x, int d) {
        for (int i = 0; i < (int) par.size(); i++) {
            if ((d >> i) & 1) {
                x = par[i][x];
            }
        }
        return x;
    }
    int lca(int x, int y) {
        if (depth[x] < depth[y]) std::swap(x, y);
        x = jump(x, depth[x] - depth[y]);
        if (x == y) return x;
        for (int i = (int) par.size() - 1; i >= 0; i--) {
            int nx = par[i][x];
            int ny = par[i][y];
            if (nx != ny) x = nx, y = ny;
        }
        return par[0][x];
    }
    bool in_subtree(int u, int v) {
        // is v in the subtree of u
        if (depth[u] > depth[v]) return false;
        int need = depth[v] - depth[u];
        int x = jump(v, need);
        if (x == u) return true;
        return false;
    }
};
int main() {
    int n, s, e, q; cin >> n >> s >> q >> e;
    e--;

    LCAJump L;
    L.init(n);

    vector<vpl> adj(n);
    vpi roads;
    vi shop(n);

    f0r(i, n - 1) {
        int u, v, w; cin >> u >> v >> w;
        u--, v--;
        adj[u].eb(v, w);
        adj[v].eb(u, w);
        L.ae(u, v);
        roads.eb(u, v);
    }

    f0r(i, s) {
        int x; re(x); x--;
        shop[x] = 1;
    }

    int ti = 0;
    vector<array<int, 2>> range(n);
    vl dep(n);

    function<void(int, int)> euler_tour = [&](int src, int par) {
        range[src][0] = ti++;
        for (auto nxt : adj[src]) {
            if (nxt.f == par) continue;
            dep[nxt.f] = dep[src] + nxt.s;
            euler_tour(nxt.f, src);
        }
        range[src][1] = ti-1;
    };
    
    L.gen(0);
    euler_tour(0, -1);
    LazySeg<ll> seg;
    seg.init(n);
    LazySeg<ll> seg2;
    seg2.init(n);

    f0r(i, n) {
        if (shop[i]) 
            seg.upd(range[i][0], range[i][0], dep[i]);
        else
            seg.upd(range[i][0], range[i][0], INF);
        seg2.upd(range[i][0], range[i][0], dep[i]);
    }


    vl ans(q);
    vl close(q);
    vl escape(q);
    vector<vpi> queries(n);
    vector<array<int, 3>> queries2;

    f0r(i, q) {
        int road, village;
        re(road, village);
        road--, village--;
        queries[village].eb(road, i);
        queries2.pb({road, village, i});
    }
    
    auto sub_update = [&](int src, ll val) {
        seg.upd(range[src][0], range[src][1], val);
    };
    auto sub_update2 = [&](int src, ll val) {
        seg2.upd(range[src][0], range[src][1], val);
    };
    auto ask = [&](int src) -> ll {
        return seg.qmin(range[src][0], range[src][1]);
    };
    auto print = [&]() {
        pr("SEG: ");
        f0r(i, n) pr(seg.qmin(range[i][0], range[i][0]),  " ");
        ps();
    };
    function<void(int, int)> reroot = [&](int src, int par) {
        // answer close queries here
        for (auto& qq : queries[src]) {
            int qid = qq.s;
            int rid = qq.f;
            int u = roads[rid].f;
            int v = roads[rid].s;
            if (dep[u] > dep[v]) swap(u, v);
            // u is parent of v
            // want to see closest of shops to src
            // case one, shop is below
            if (L.in_subtree(v, src)) {
                // everything else above is blocked
                sub_update(0, INF);
                sub_update(v, -INF);
                close[qid] = ask(v);
                
                sub_update(0, -INF);
                sub_update(v, INF);
            } else {
                // everthing in v is blocked
                sub_update(v, INF);
                close[qid] = ask(0);
                sub_update(v, -INF);
            }
        }
        // answer can escape queries
        if (src == e) {
            // you are at the escape point
            for (auto& qq : queries2) {
                int qid = qq[2];
                int rid = qq[0];
                int vid = qq[1];
                int u = roads[rid].f;
                int v = roads[rid].s;

                if (dep[u] > dep[v]) swap(u, v);
               
                if (L.in_subtree(v, src)) {
                    // everything else above is blocked
                    sub_update2(0, INF);
                    sub_update2(v, -INF);
                    escape[qid] = seg2.qmin(range[vid][0], range[vid][0]);
                    sub_update2(0, -INF);
                    sub_update2(v, INF);
                } else {
                    // everthing in v is blocked
                    sub_update2(v, INF);
                    escape[qid] = seg2.qmin(range[vid][0], range[vid][0]);
                    sub_update2(v, -INF);
                }
            }
        }
        for (auto go : adj[src]) { 
            int nxt = go.f;
            if (nxt == par) continue;
            int w = go.s;
            sub_update(0, w);
            sub_update(nxt, -2*w);

            sub_update2(0, w);
            sub_update2(nxt, -2*w);

            reroot(nxt, src);

            sub_update(0, -w);
            sub_update(nxt, 2*w);

            sub_update2(0, -w);
            sub_update2(nxt, 2*w);
        }
    };
    reroot(0, -1);
    f0r(i, q) {
        if (escape[i] < CUT) {
            ps("escaped");
        } else {
            if (close[i] < CUT) {
                ps(close[i]);
            } else {
                ps("oo");
            }
        }
    }
}

Compilation message (stderr)

valley.cpp: In function 'int main()':
valley.cpp:395:10: warning: variable 'print' set but not used [-Wunused-but-set-variable]
  395 |     auto print = [&]() {
      |          ^~~~~
valley.cpp: In function 'void io::setIn(std::string)':
valley.cpp:153:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  153 |     void setIn(string s) { freopen(s.c_str(), "r", stdin); }
      |                            ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
valley.cpp: In function 'void io::setOut(std::string)':
valley.cpp:154:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  154 |     void setOut(string s) { freopen(s.c_str(), "w", stdout); }
      |                             ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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