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Submission #650469

# Submission time Handle Problem Language Result Execution time Memory
650469 2022-10-13T20:59:32 Z leroycut Valley (BOI19_valley) C++17
100 / 100
 210 ms 43548 KB 
#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;

const int N = 1e5 + 3, S = 20;
const ll INF = 1e18;
int tin[N], tout[N], up[N][S];
bool sh[N];
ll mag[N], len[N], up_mag[N][S];
int t = 1;

struct edge{
    int v, u;
};

edge ed[N];
vector<vector<pair<int, ll>>> g;


void dfs0(int v, int p, ll l){
    if(p != -1){
        up[v][0] = p;
    }
    tin[v] = t++;
    len[v] = l;
    for(auto i : g[v]){
        if(i.first == p) continue;
        dfs0(i.first, v, l + i.second);
    }
    tout[v] = t++;
}

void cal_mag(int v, int p){
    ll mi = (sh[v] ? len[v] : INF);
    if(mi != INF) mi -= 2 * len[v];
    for(auto i : g[v]){
        if(i.first == p) continue;
        cal_mag(i.first, v);
        if(mag[i.first] != INF)
            mi = min(mi, mag[i.first] + 2 * i.second);
    }
    mag[v] = mi;
    up_mag[v][0] = mi;
}




int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int n, s, q, e;
    cin >> n >> s >> q >> e;
    g.resize(n + 1);

    for(int i = 1; i <= n - 1; ++i){
        int x, y;
        ll w;
        cin >> x >> y >> w;
        ed[i] = {x, y};
        g[x].push_back({y, w});
        g[y].push_back({x, w});
    }

    for(int i = 0; i < s; ++i){
        int a;
        cin >> a;
        sh[a] = true;
    }

    dfs0(e, -1, 0);
    cal_mag(e, -1);

    for(int j = 1; j < S; ++j){
        for(int i = 1; i <= n; ++i){
            up[i][j] = up[up[i][j - 1]][j - 1];
            up_mag[i][j] = min(up_mag[i][j - 1], up_mag[up[i][j - 1]][j - 1]);
        }
    }
    
    // for(int i = 1; i <= n; ++i){
    //     cout << len[i] << " " << mag[i] << " " << i << "\n";
    // }

    for(int i = 1; i <= q; ++i){
        int ro, v;
        cin >> ro >> v;
        int p, ch;
        p = ed[ro].u;
        ch = ed[ro].v;
        ll l = len[v];
        if(tin[ed[ro].u] > tin[ed[ro].v]) swap(p, ch);
        // cout << ch << " " << v << "|\n";
        if(tin[ch] <= tin[v] && tout[v] <= tout[ch]){
            ll ans = mag[v];
            // cout << v << " " << up[v][0] << "!\n";
            for(int k = S - 1; k >= 0; --k){
                int cur = up[v][k];
                if(tin[ch] <= tin[cur] && tout[cur] <= tout[ch]){
                    // cout << k << " " << v << " " << mag[v] << "*\n";
                    ans = min(ans, up_mag[v][k]);
                    v = cur;
                }
            }
            ans = min(ans, mag[ch]);
            // cout << v << " " << mag[v] << " " << up_mag[4][2] << "\n"; 
            if(ans == INF){
                cout << "oo\n";
            }else{
                cout << ans + l << "\n";
            }
        }else{
            cout << "escaped\n";
        }
    }
}

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 468 KB Output is correct
2 Correct 2 ms 464 KB Output is correct
3 Correct 2 ms 468 KB Output is correct
4 Correct 3 ms 468 KB Output is correct

Subtask #2
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 468 KB Output is correct
2 Correct 2 ms 464 KB Output is correct
3 Correct 2 ms 468 KB Output is correct
4 Correct 3 ms 468 KB Output is correct
5 Correct 1 ms 724 KB Output is correct
6 Correct 1 ms 720 KB Output is correct
7 Correct 2 ms 724 KB Output is correct
8 Correct 1 ms 724 KB Output is correct
9 Correct 2 ms 724 KB Output is correct
10 Correct 2 ms 724 KB Output is correct
11 Correct 2 ms 724 KB Output is correct
12 Correct 2 ms 724 KB Output is correct
13 Correct 2 ms 724 KB Output is correct
14 Correct 1 ms 724 KB Output is correct

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 136 ms 35176 KB Output is correct
2 Correct 174 ms 34972 KB Output is correct
3 Correct 178 ms 35156 KB Output is correct
4 Correct 177 ms 37016 KB Output is correct
5 Correct 167 ms 37196 KB Output is correct
6 Correct 206 ms 39244 KB Output is correct

Subtask #4
41.0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 468 KB Output is correct
2 Correct 2 ms 464 KB Output is correct
3 Correct 2 ms 468 KB Output is correct
4 Correct 3 ms 468 KB Output is correct
5 Correct 1 ms 724 KB Output is correct
6 Correct 1 ms 720 KB Output is correct
7 Correct 2 ms 724 KB Output is correct
8 Correct 1 ms 724 KB Output is correct
9 Correct 2 ms 724 KB Output is correct
10 Correct 2 ms 724 KB Output is correct
11 Correct 2 ms 724 KB Output is correct
12 Correct 2 ms 724 KB Output is correct
13 Correct 2 ms 724 KB Output is correct
14 Correct 1 ms 724 KB Output is correct
15 Correct 136 ms 35176 KB Output is correct
16 Correct 174 ms 34972 KB Output is correct
17 Correct 178 ms 35156 KB Output is correct
18 Correct 177 ms 37016 KB Output is correct
19 Correct 167 ms 37196 KB Output is correct
20 Correct 206 ms 39244 KB Output is correct
21 Correct 150 ms 38436 KB Output is correct
22 Correct 146 ms 38220 KB Output is correct
23 Correct 155 ms 38420 KB Output is correct
24 Correct 186 ms 40544 KB Output is correct
25 Correct 183 ms 43548 KB Output is correct
26 Correct 149 ms 38492 KB Output is correct
27 Correct 176 ms 38212 KB Output is correct
28 Correct 196 ms 38476 KB Output is correct
29 Correct 180 ms 40016 KB Output is correct
30 Correct 210 ms 41620 KB Output is correct
31 Correct 134 ms 38476 KB Output is correct
32 Correct 181 ms 38432 KB Output is correct
33 Correct 173 ms 38732 KB Output is correct
34 Correct 206 ms 40596 KB Output is correct
35 Correct 200 ms 43456 KB Output is correct
36 Correct 165 ms 40440 KB Output is correct