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Submission #836285

# Submission time Handle Problem Language Result Execution time Memory
836285 2023-08-24T09:46:24 Z lamduybao03 Valley (BOI19_valley) C++14
100 / 100
 440 ms 69144 KB 
#include <bits/stdc++.h>
#define int long long
#define sqr(x) ((x) * (x))
using namespace std;
typedef pair<int, int> pi;
typedef pair<pi, int> ppi;
const int mod = 1e9+7;
const int inv_2 = (mod+1) / 2;


int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    #ifdef LOCAL
        freopen("input.txt", "r", stdin);
        //freopen("output.txt", "w", stdout);
    #endif
    int n, s, q, e;
    cin >> n >> s >> q >> e;
    map<pi, int> edge_to_id;
    vector<vector<pi>> adj(n+1);
    for(int i = 1; i < n; i++) {
        int u, v, w;
        cin >> u >> v >> w;
        adj[u].push_back({v, w});
        adj[v].push_back({u, w});
        edge_to_id[{u, v}] = i;
        edge_to_id[{v, u}] = i;
    }
    vector<int> par(n+1);
    vector<int> d(n+1);
    vector<int> h(n+1);
    vector<int> vis(n+1);
    vector<int> pos(n+1);
    vector<int> down(n+1, 1e18);
    for(int i = 0; i < s; i++) {
        int u;
        cin >> u;
        down[u] = 0;
    }
    function<void(int)> dfs = [&] (int u) {
        vis[u] = 1;
        for(auto p : adj[u]) {
            int v = p.first;
            int w = p.second;
            if(!vis[v]) {
                pos[edge_to_id[{u, v}]] = v;
                par[v] = u;
                d[v] = d[u] + w;
                h[v] = h[u] + 1;
                dfs(v);
                down[u] = min(down[u], down[v] + w);
            }
        }
    };
    dfs(e);
    for(int i = 1; i <= n; i++)
        down[i] = down[i] - d[i];
    vector<vector<int>> p(20, vector<int> (n+1));
    vector<vector<int>> dis(20, vector<int> (n+1, 1e18));
    for(int i = 1; i <= n; i++) {
        p[0][i] = par[i];
        dis[0][i] = down[i];
    }
    for(int i = 1; i < 20; i++) {
        for(int j = 1; j <= n; j++) {
            p[i][j] = p[i-1][p[i-1][j]];
            dis[i][j] = min(dis[i-1][j], dis[i-1][p[i-1][j]]);
        }
    }
    function<int(int, int)> lca = [&] (int u, int v) {
        if(h[u] < h[v]) {
            swap(u, v);
        }
        int delta = h[u] - h[v];
        for(int i = 0; i < 20; i++) {
            if(delta & (1 << i)) {
                u = p[i][u];
            }
        }
        if(u == v)
            return u;
        for(int i = 19; i >= 0; i--) {
            if(p[i][u] != p[i][v]) {
                u = p[i][u];
                v = p[i][v];
            }
        }
        u = p[0][u];
        v = p[0][v];
        if(u != v)
            throw 0;
        return u;
    };
    function<int(int, int)> get = [&] (int u, int k) {
        int s = 1e18;
        for(int i = 0; i < 20; i++) {
            if(k & (1 << i)) {
                s = min(s, dis[i][u]);
                u = p[i][u];
            }
        }
        return s;
    };
    while(q--) {
        int i, u;
        cin >> i >> u;
        int v = pos[i];
        if(lca(u, v) != v) {
            cout << "escaped\n";
        }
        else {
            int delta = h[u] - h[v] + 1;
            int s = get(u, delta) + d[u];
            if(s > 1e17)
                cout << "oo\n";
            else
                cout << s << "\n";
        }
    }
}

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 340 KB Output is correct
2 Correct 3 ms 460 KB Output is correct
3 Correct 3 ms 488 KB Output is correct
4 Correct 4 ms 468 KB Output is correct

Subtask #2
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 340 KB Output is correct
2 Correct 3 ms 460 KB Output is correct
3 Correct 3 ms 488 KB Output is correct
4 Correct 4 ms 468 KB Output is correct
5 Correct 2 ms 844 KB Output is correct
6 Correct 2 ms 852 KB Output is correct
7 Correct 2 ms 852 KB Output is correct
8 Correct 2 ms 852 KB Output is correct
9 Correct 2 ms 852 KB Output is correct
10 Correct 2 ms 864 KB Output is correct
11 Correct 3 ms 840 KB Output is correct
12 Correct 2 ms 852 KB Output is correct
13 Correct 2 ms 840 KB Output is correct
14 Correct 2 ms 852 KB Output is correct

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 326 ms 57848 KB Output is correct
2 Correct 272 ms 61428 KB Output is correct
3 Correct 440 ms 61680 KB Output is correct
4 Correct 303 ms 64668 KB Output is correct
5 Correct 270 ms 64780 KB Output is correct
6 Correct 304 ms 68284 KB Output is correct

Subtask #4
41.0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 340 KB Output is correct
2 Correct 3 ms 460 KB Output is correct
3 Correct 3 ms 488 KB Output is correct
4 Correct 4 ms 468 KB Output is correct
5 Correct 2 ms 844 KB Output is correct
6 Correct 2 ms 852 KB Output is correct
7 Correct 2 ms 852 KB Output is correct
8 Correct 2 ms 852 KB Output is correct
9 Correct 2 ms 852 KB Output is correct
10 Correct 2 ms 864 KB Output is correct
11 Correct 3 ms 840 KB Output is correct
12 Correct 2 ms 852 KB Output is correct
13 Correct 2 ms 840 KB Output is correct
14 Correct 2 ms 852 KB Output is correct
15 Correct 326 ms 57848 KB Output is correct
16 Correct 272 ms 61428 KB Output is correct
17 Correct 440 ms 61680 KB Output is correct
18 Correct 303 ms 64668 KB Output is correct
19 Correct 270 ms 64780 KB Output is correct
20 Correct 304 ms 68284 KB Output is correct
21 Correct 270 ms 61164 KB Output is correct
22 Correct 250 ms 60932 KB Output is correct
23 Correct 365 ms 61204 KB Output is correct
24 Correct 382 ms 64572 KB Output is correct
25 Correct 356 ms 69144 KB Output is correct
26 Correct 270 ms 61100 KB Output is correct
27 Correct 261 ms 60920 KB Output is correct
28 Correct 364 ms 61252 KB Output is correct
29 Correct 394 ms 63420 KB Output is correct
30 Correct 289 ms 65896 KB Output is correct
31 Correct 317 ms 61148 KB Output is correct
32 Correct 274 ms 61076 KB Output is correct
33 Correct 308 ms 61320 KB Output is correct
34 Correct 301 ms 64352 KB Output is correct
35 Correct 347 ms 68864 KB Output is correct
36 Correct 277 ms 64444 KB Output is correct