Submission #1096293

#	Time	Username	Problem	Language	Result	Execution time	Memory
1096293		anhthi	Valley (BOI19_valley)	C++14	100 / 100	149 ms	46416 KiB

valley

#include <bits/stdc++.h>

using namespace std;

#define fi first
#define se second
#define ll long long
#define mp(x, y) make_pair(x, y)
#define sz(v) ((int) (v).size())
#define all(v) (v).begin(), (v).end()
#define MASK(i) (1LL << (i))
#define BIT(x, y) (((x) >> (y)) & 1)
#define pb push_back
#define max_rng *max_element
#define min_rng *min_element
#define rep(i, n) for(int i = 1, _n = (n); i <= _n; ++i)
#define forn(i, a, b) for(int i = (a), _b = (b); i <= _b; ++i)
#define ford(i, a, b) for(int i = (a), _b = (b); i >= _b; --i)

template <class X, class Y>
    inline bool maximize(X &x, Y y) {
        return (x < y ? x = y, true : false);
    }

template <class X, class Y>
    inline bool minimize(X &x, Y y) {
        return (x > y ? x = y, true : false);
    }

template <class X>
    inline void compress(vector<X> &a) {
        sort(all(a));
        a.resize(unique(all(a)) - a.begin());
    }

int ctz(ll x) { return __builtin_ctzll(x); }
int lg(ll x) { return 63 - __builtin_clzll(x); }
int popcount(ll x) { return __builtin_popcount(x); }

mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) {
    return l + abs((ll) rng()) % (r - l + 1);
}

const ll oo = (ll) 1e17;
const int inf = (ll) 2e9 + 7, mod = (ll) 123456789;

const int N = 1e5 + 5, BASE = 307, LOG = 20;

void add(int &x, int y) { x += y; if (x >= mod) x -= mod; }
void sub(int &x, int y) { x -= y; if (x < 0) x += mod; }

int n, S, Q, H;
struct Edge {
    int u, v, w;
    void input() {
        cin >> u >> v >> w;
    }
} e[N];
vector<pair<int, int>> g[N];
bool rescue[N];

int haveIn[N];

int timer = 0;
int in[N], out[N];

int h[N];
int par[N][LOG + 5];
void calc(int u, int p) {
    in[u] = ++timer;
    haveIn[u] = rescue[u];
    forn(i, 1, LOG) par[u][i] = par[par[u][i-1]][i-1];
    for (pair<int, int> i : g[u]) {
        int v = i.first;
        if (v == p) continue;
        par[v][0] = u;
        h[v] = h[u] + 1;
        calc(v, u);
        haveIn[u] += haveIn[v];
    }
    out[u] = timer;
}
ll dist[N];
ll dp[N], value[N][LOG + 5];
void dfs(int u, int p) {
    dp[u] = rescue[u] ? 0 : oo;
    for (pair<int, int> i : g[u]) {
        int v = i.first;
        if (v == p) continue;
        dist[v] = dist[u] + e[i.second].w;
        dfs(v, u);
        minimize(dp[u], dp[v] + e[i.second].w);
    }
}
void build_stb(int u, int p) {
    value[u][0] = min(-dist[u] + dp[u], -dist[p] + dp[p]);
    forn(i, 1, LOG) {
        value[u][i] = min(value[u][i-1], value[par[u][i-1]][i-1]);
    }
    for (pair<int, int> i : g[u]) if (i.first != p) {
        build_stb(i.first, u);
    }
    return;
}

bool isIn(int root, int u) {
    return in[root] <= in[u] && in[u] <= out[root];
}
int lift(int u, int k) {
    for (; k > 0; k -= k & -k)
        u = par[u][ctz(k)];
    return u;
}
ll getMin(int u, int k) {
    ll ans = oo;
    for (; k > 0; k -= k & -k) {
        minimize(ans, value[u][ctz(k)]);
        u = par[u][ctz(k)];
    }
    return ans;
}

signed main(void) {

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

    cin >> n >> S >> Q >> H;
    rep(i, n - 1) {
        e[i].input();
        g[e[i].u].pb(mp(e[i].v, i));
        g[e[i].v].pb(mp(e[i].u, i));
    }
    rep(i, S) {
        int u;
        cin >> u;
        rescue[u] = true;
    }

    calc(H, 0);
    dfs(H, 0);

    memset(value, 0x3f, sizeof value);
    build_stb(H, 0);

    #define ins(x) { cout << x << '\n'; }
    rep(_, Q) {
        int ban, node;
        cin >> ban >> node;

        Edge cur = e[ban];
        if (h[cur.u] > h[cur.v])
            swap(cur.u, cur.v);

        if (!isIn(cur.v, node)) {
            ins("escaped");
            continue;
        }

        if (!haveIn[cur.v]) {
            ins("oo");
            continue;
        }

        ll ans = oo;
        if (haveIn[node]) minimize(ans, dp[node]);

        minimize(ans, getMin(node, h[node] - h[cur.v]) + dist[node]);

        ins(ans);
    }

    return 0;
}

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