oj.uz

답안 #969352

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
969352 2024-04-25T03:22:30 Z eysbutno Valley (BOI19_valley) C++17
100 / 100
 195 ms 37268 KB 
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = array<int, 2>;
#define all(x) begin(x), end(x)
#define sz(x) (int) (x).size()

#ifdef LOCAL
#include "../src/debug.hpp"
#else
#define debug(...) 420
#endif
// g++ -DLOCAL -Wall Practice.cpp -o bin

template<class T> bool smax(T &a, T b) {
    return a < b ? a = b, 1 : 0;
}
template<class T> bool smin(T &a, T b) {
    return a > b ? a = b, 1 : 0;
}
void solve() {
    int n, s, q, e;
    cin >> n >> s >> q >> e; --e;
    vector<vector<pii>> adj(n);
    vector<array<int, 3>> edges(n - 1);
    for (int i = 1; i < n; i++) {
        int u, v, w;
        cin >> u >> v >> w;
        --u, --v;
        adj[u].push_back({v, w});
        adj[v].push_back({u, w});
        edges[i - 1] = {u, v, w};
    }
    const ll INF = 1e18;
    vector<ll> dp(n, INF), dist(n);
    for (int i = 0; i < s; i++) {
        int c; cin >> c;
        dp[--c] = 0ll;
    }
    const int LOG = 32 - __builtin_clz(n);
    vector lift(LOG, vector(n, 0));
    vector data(LOG, vector(n, INF));
    vector<int> dep(n);
    auto dfs = [&](int u, int p, auto&& dfs) -> void {
        for (auto [v, w] : adj[u]) if (v != p) {
            dist[v] = dist[u] + w;
            dep[v] = dep[u] + 1;
            lift[0][v] = u;
            for (int i = 1; i < LOG; i++) {
                lift[i][v] = lift[i - 1][lift[i - 1][v]];
            }
            dfs(v, u, dfs);
            smin(dp[u], dp[v] + w);
        }
    }; dfs(e, -1, dfs);
    auto dfs2 = [&](int u, int p, auto&& dfs2) -> void {
        for (auto [v, w] : adj[u]) if (v != p) {
            data[0][v] = dp[u] - dist[u];
            for (int i = 1; i < LOG; i++) {
                data[i][v] = min(data[i - 1][v], data[i - 1][lift[i - 1][v]]);
            }
            dfs2(v, u, dfs2);
        }
    }; dfs2(e, -1, dfs2);
    for (auto &[u, v, w] : edges) {
        if (dep[u] > dep[v]) swap(u, v);
    }
    auto jump = [&](int x, int d) -> array<ll, 2> {
        array<ll, 2> res = {INF, x};
        for (int i = LOG - 1; i >= 0; i--) {
            if (d >> i & 1) {
                smin(res[0], data[i][res[1]]);
                res[1] = lift[i][res[1]];
            }
        }
        return res;
    };
    auto qry = [&](int idx, int r) -> void {
        int dx = dep[r] - dep[edges[idx][1]];
        array<ll, 2> res = (dx < 0 ? array<ll, 2>{0, 0} : jump(r, dx));
        if (dx < 0 || jump(r, dx)[1] != edges[idx][1]) {
            cout << "escaped" << "\n";
        } else {
            ll ans = min(res[0] + dist[r], dp[r]);
            cout << (ans < INF ? to_string(ans) : "oo") << "\n";
        }
    };
    while (q--) {
        int i, r;
        cin >> i >> r;
        qry(i - 1, r - 1);
    }
}
int main() {
    cin.tie(0) -> sync_with_stdio(0);
    int t = 1; // cin >> t;
    while (t--) solve();
}
/**
 * Root the tree at E. Checking if it's possible
 * to escape is trivial. Otherwise, do the following:
 * 1. Calculate an array DP, which is the least time it
 * will take to reach some shop inside this subtree.
 * 2. Calculate a binary lift array, where each original
 * index stores the best value of:
 * min(shopdist) - 2 * dist(cur_index)
 * ... or in other words:
 * dp[index] - dist(cur_index).
*/

Subtask #1
9.0 / 9.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 348 KB Output is correct
2 Correct 2 ms 548 KB Output is correct
3 Correct 2 ms 600 KB Output is correct
4 Correct 2 ms 552 KB Output is correct

Subtask #2
27.0 / 27.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 348 KB Output is correct
2 Correct 2 ms 548 KB Output is correct
3 Correct 2 ms 600 KB Output is correct
4 Correct 2 ms 552 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 600 KB Output is correct
9 Correct 1 ms 604 KB Output is correct
10 Correct 1 ms 604 KB Output is correct
11 Correct 1 ms 604 KB Output is correct
12 Correct 1 ms 548 KB Output is correct
13 Correct 1 ms 604 KB Output is correct
14 Correct 1 ms 604 KB Output is correct

Subtask #3
23.0 / 23.0

# 결과 실행 시간 메모리 Grader output
1 Correct 136 ms 30384 KB Output is correct
2 Correct 138 ms 30136 KB Output is correct
3 Correct 148 ms 29972 KB Output is correct
4 Correct 153 ms 31228 KB Output is correct
5 Correct 146 ms 31392 KB Output is correct
6 Correct 180 ms 32696 KB Output is correct

Subtask #4
41.0 / 41.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 348 KB Output is correct
2 Correct 2 ms 548 KB Output is correct
3 Correct 2 ms 600 KB Output is correct
4 Correct 2 ms 552 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 600 KB Output is correct
9 Correct 1 ms 604 KB Output is correct
10 Correct 1 ms 604 KB Output is correct
11 Correct 1 ms 604 KB Output is correct
12 Correct 1 ms 548 KB Output is correct
13 Correct 1 ms 604 KB Output is correct
14 Correct 1 ms 604 KB Output is correct
15 Correct 136 ms 30384 KB Output is correct
16 Correct 138 ms 30136 KB Output is correct
17 Correct 148 ms 29972 KB Output is correct
18 Correct 153 ms 31228 KB Output is correct
19 Correct 146 ms 31392 KB Output is correct
20 Correct 180 ms 32696 KB Output is correct
21 Correct 124 ms 33856 KB Output is correct
22 Correct 136 ms 33316 KB Output is correct
23 Correct 133 ms 33468 KB Output is correct
24 Correct 159 ms 34760 KB Output is correct
25 Correct 195 ms 37268 KB Output is correct
26 Correct 155 ms 33720 KB Output is correct
27 Correct 124 ms 33520 KB Output is correct
28 Correct 141 ms 33332 KB Output is correct
29 Correct 147 ms 34488 KB Output is correct
30 Correct 175 ms 35516 KB Output is correct
31 Correct 121 ms 33936 KB Output is correct
32 Correct 125 ms 33408 KB Output is correct
33 Correct 140 ms 33468 KB Output is correct
34 Correct 152 ms 34744 KB Output is correct
35 Correct 172 ms 36784 KB Output is correct
36 Correct 147 ms 35000 KB Output is correct