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Submission #911086

# Submission time Handle Problem Language Result Execution time Memory
911086 2024-01-18T12:39:08 Z VMaksimoski008 Valley (BOI19_valley) C++14
100 / 100
 368 ms 36548 KB 
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;

const int LOG = 18, maxn = 1e5 + 5;
 
int n, s, q, e, timer = 0;
vector<vector<pii> > graph;
int store[maxn+1], in[maxn+1], out[maxn+1], depth[maxn+1], up[maxn+1][LOG];
ll dp[maxn+1], dist[maxn+1], mn[maxn+1][LOG];
 
void dfs(int u, int p) {
    in[u] = timer++;
    dp[u] = (store[u] ? dist[u] : 1e17);
 
    for(auto &[v, w] : graph[u]) {
        if(v == p) continue;
        dist[v] = dist[u] + w;
        dfs(v, u);
        dp[u] = min(dp[u], dp[v]);
    }
 
    out[u] = timer;
}

void dfs2(int u, int p) {
    for(int i=1; i<LOG; i++) {
        up[u][i] = up[ up[u][i-1] ][i-1];
        mn[u][i] = min(mn[u][i-1], mn[ up[u][i-1] ][i-1]);
    }

    for(auto &[v, _] : graph[u]) {
        if(v == p) continue;
        up[v][0] = u;
        mn[v][0] = dp[u];
        dfs2(v, u);
    }
}
 
bool anc(int u, int v) { return (in[u] <= in[v] && out[u] >= out[v]); }
 
int32_t main() {
    cin >> n >> s >> q >> e;
    vector<pii> edges;
    graph.resize(n+1);
 
    for(int i=0; i<n-1; i++) {
        int a, b, w;
        cin >> a >> b >> w;
        edges.push_back({ a, b });
        graph[a].push_back({ b, w });
        graph[b].push_back({ a, w });
    }
 
    for(int i=0; i<s; i++) {
        int x;
        cin >> x;
        store[x] = 1;
    }
 
    dfs(e, 0);
    for(int u=1; u<=n; u++) dp[u] -= 2 * dist[u];
    dfs2(e, 0);
 
    while(q--) {
        int I, R;
        cin >> I >> R;
        pii edge = edges[I-1];
 
        if(in[edge.first] < in[edge.second]) swap(edge.first, edge.second);
        if(anc(edge.first, R) == anc(edge.first, e)) {
            cout << "escaped\n";
            continue;
        }

        ll ans = dp[R] + dist[R];
        int u = R;
        
        for(int j=LOG-1; j>=0; j--) {
            if(up[u][j] == 0) continue;
            if(!anc(edge.first, up[u][j])) continue;
            ans = min(ans, dist[R] + mn[u][j]);
            u = up[u][j];
        }

        if(ans >= 1e15) cout << "oo\n";
        else cout << ans << '\n';
    }

    return 0;
}

Compilation message

valley.cpp: In function 'void dfs(int, int)':
valley.cpp:17:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   17 |     for(auto &[v, w] : graph[u]) {
      |               ^
valley.cpp: In function 'void dfs2(int, int)':
valley.cpp:33:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   33 |     for(auto &[v, _] : graph[u]) {
      |               ^

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 2396 KB Output is correct
2 Correct 15 ms 2584 KB Output is correct
3 Correct 16 ms 2396 KB Output is correct
4 Correct 15 ms 2396 KB Output is correct

Subtask #2
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 2396 KB Output is correct
2 Correct 15 ms 2584 KB Output is correct
3 Correct 16 ms 2396 KB Output is correct
4 Correct 15 ms 2396 KB Output is correct
5 Correct 4 ms 2652 KB Output is correct
6 Correct 3 ms 2652 KB Output is correct
7 Correct 3 ms 2760 KB Output is correct
8 Correct 3 ms 2652 KB Output is correct
9 Correct 3 ms 2652 KB Output is correct
10 Correct 3 ms 2652 KB Output is correct
11 Correct 4 ms 2652 KB Output is correct
12 Correct 3 ms 2652 KB Output is correct
13 Correct 3 ms 2652 KB Output is correct
14 Correct 3 ms 2652 KB Output is correct

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 327 ms 31920 KB Output is correct
2 Correct 335 ms 31532 KB Output is correct
3 Correct 347 ms 31708 KB Output is correct
4 Correct 368 ms 33284 KB Output is correct
5 Correct 347 ms 33656 KB Output is correct
6 Correct 357 ms 35352 KB Output is correct

Subtask #4
41.0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 2396 KB Output is correct
2 Correct 15 ms 2584 KB Output is correct
3 Correct 16 ms 2396 KB Output is correct
4 Correct 15 ms 2396 KB Output is correct
5 Correct 4 ms 2652 KB Output is correct
6 Correct 3 ms 2652 KB Output is correct
7 Correct 3 ms 2760 KB Output is correct
8 Correct 3 ms 2652 KB Output is correct
9 Correct 3 ms 2652 KB Output is correct
10 Correct 3 ms 2652 KB Output is correct
11 Correct 4 ms 2652 KB Output is correct
12 Correct 3 ms 2652 KB Output is correct
13 Correct 3 ms 2652 KB Output is correct
14 Correct 3 ms 2652 KB Output is correct
15 Correct 327 ms 31920 KB Output is correct
16 Correct 335 ms 31532 KB Output is correct
17 Correct 347 ms 31708 KB Output is correct
18 Correct 368 ms 33284 KB Output is correct
19 Correct 347 ms 33656 KB Output is correct
20 Correct 357 ms 35352 KB Output is correct
21 Correct 344 ms 31684 KB Output is correct
22 Correct 328 ms 31172 KB Output is correct
23 Correct 318 ms 31200 KB Output is correct
24 Correct 332 ms 33292 KB Output is correct
25 Correct 349 ms 36548 KB Output is correct
26 Correct 333 ms 31980 KB Output is correct
27 Correct 313 ms 31648 KB Output is correct
28 Correct 361 ms 31392 KB Output is correct
29 Correct 360 ms 33096 KB Output is correct
30 Correct 335 ms 34188 KB Output is correct
31 Correct 314 ms 31920 KB Output is correct
32 Correct 311 ms 31748 KB Output is correct
33 Correct 329 ms 31772 KB Output is correct
34 Correct 351 ms 33476 KB Output is correct
35 Correct 341 ms 36548 KB Output is correct
36 Correct 315 ms 34216 KB Output is correct