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Submission #922718

# Submission time Handle Problem Language Result Execution time Memory
922718 2024-02-06T04:00:03 Z Alihan_8 Valley (BOI19_valley) C++17
100 / 100
 286 ms 65940 KB 
#include <bits/stdc++.h>

using namespace std;

#define all(x) x.begin(), x.end()
#define ar array
#define pb push_back
#define ln '\n'
#define int long long

using i64 = long long;

template <class F, class _S>
bool chmin(F &u, const _S &v){
    bool flag = false;
    if ( u > v ){
        u = v; flag |= true;
    }
    return flag;
}

template <class F, class _S>
bool chmax(F &u, const _S &v){
    bool flag = false;
    if ( u < v ){
        u = v; flag |= true;
    }
    return flag;
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, s, q, rt;
    cin >> n >> s >> q >> rt;
    --rt;

    vector <vector<ar<int,3>>> G(n);

    for ( int i = 0; i + 1 < n; i++ ){
        int u, v, w; cin >> u >> v >> w;
        --u, --v;
        G[u].pb({v, w, i});
        G[v].pb({u, w, i});
    }

    const int inf = 1e18;

    vector <int> dp(n, inf);

    for ( int i = 0; i < s; i++ ){
        int u; cin >> u;
        dp[--u] = 0;
    }

    vector <ar<int,2>> tree(n - 1);

    vector <vector<int>> up(n, vector <int> (20, rt)), val(n, vector <int> (20, inf));

    vector <int> tin(n), tout(n), d(n);

    int ct = 0;

    auto Dp = [&](auto Dp, int u, int p) -> void{
        for ( auto &[v, w, i]: G[u] ){
            if ( v != p ){
                Dp(Dp, v, u);
                chmin(dp[u], dp[v] + w);
            }
        }
    };

    Dp(Dp, rt, rt);

    auto dfs = [&](auto dfs, int u, int p) -> void{
        tin[u] = ++ct;
        up[u][0] = p;
        val[u][0] = dp[u] - d[u];
        for ( int i = 1; i < 20; i++ ){
            up[u][i] = up[up[u][i - 1]][i - 1];
            val[u][i] = min(val[u][i - 1], val[up[u][i - 1]][i - 1]);
        }
        for ( auto &[v, w, i]: G[u] ){
            if ( v != p ){
                tree[i] = {u, v};
                d[v] = d[u] + w;
                dfs(dfs, v, u);
            }
        } tout[u] = ct;
    };

    dfs(dfs, rt, rt);

    auto isAnc = [&](int u, int v){
        return tin[u] <= tin[v] && tout[u] >= tout[v];
    };

    while ( q-- ){
        int i, r; cin >> i >> r;
        --i, --r;
        if ( !isAnc(tree[i][1], r) ){
            cout << "escaped\n";
            continue;
        }
        int opt = dp[r], u = r, v = tree[i][1], c = d[r];
        for ( int j = 19; j >= 0; j-- ){
            if ( d[up[r][j]] >= d[v] ){
                chmin(opt, val[r][j] + c);
                r = up[r][j];
            }
        }
        chmin(opt, dp[v] - d[v] + d[u]);
        if ( opt >= 1e16 ){
            cout << "oo\n";
        } else cout << opt << ln;
    }

    cout << '\n';
}

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 348 KB Output is correct
2 Correct 2 ms 604 KB Output is correct
3 Correct 2 ms 408 KB Output is correct
4 Correct 2 ms 604 KB Output is correct

Subtask #2
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 348 KB Output is correct
2 Correct 2 ms 604 KB Output is correct
3 Correct 2 ms 408 KB Output is correct
4 Correct 2 ms 604 KB Output is correct
5 Correct 2 ms 856 KB Output is correct
6 Correct 1 ms 860 KB Output is correct
7 Correct 1 ms 860 KB Output is correct
8 Correct 1 ms 860 KB Output is correct
9 Correct 1 ms 860 KB Output is correct
10 Correct 1 ms 860 KB Output is correct
11 Correct 1 ms 980 KB Output is correct
12 Correct 1 ms 860 KB Output is correct
13 Correct 1 ms 980 KB Output is correct
14 Correct 2 ms 860 KB Output is correct

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 167 ms 53832 KB Output is correct
2 Correct 180 ms 53460 KB Output is correct
3 Correct 204 ms 53724 KB Output is correct
4 Correct 251 ms 57104 KB Output is correct
5 Correct 207 ms 57168 KB Output is correct
6 Correct 271 ms 61264 KB Output is correct

Subtask #4
41.0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 348 KB Output is correct
2 Correct 2 ms 604 KB Output is correct
3 Correct 2 ms 408 KB Output is correct
4 Correct 2 ms 604 KB Output is correct
5 Correct 2 ms 856 KB Output is correct
6 Correct 1 ms 860 KB Output is correct
7 Correct 1 ms 860 KB Output is correct
8 Correct 1 ms 860 KB Output is correct
9 Correct 1 ms 860 KB Output is correct
10 Correct 1 ms 860 KB Output is correct
11 Correct 1 ms 980 KB Output is correct
12 Correct 1 ms 860 KB Output is correct
13 Correct 1 ms 980 KB Output is correct
14 Correct 2 ms 860 KB Output is correct
15 Correct 167 ms 53832 KB Output is correct
16 Correct 180 ms 53460 KB Output is correct
17 Correct 204 ms 53724 KB Output is correct
18 Correct 251 ms 57104 KB Output is correct
19 Correct 207 ms 57168 KB Output is correct
20 Correct 271 ms 61264 KB Output is correct
21 Correct 153 ms 56888 KB Output is correct
22 Correct 183 ms 56788 KB Output is correct
23 Correct 185 ms 57196 KB Output is correct
24 Correct 257 ms 60904 KB Output is correct
25 Correct 278 ms 65876 KB Output is correct
26 Correct 170 ms 57064 KB Output is correct
27 Correct 173 ms 56892 KB Output is correct
28 Correct 195 ms 57084 KB Output is correct
29 Correct 253 ms 59604 KB Output is correct
30 Correct 286 ms 62340 KB Output is correct
31 Correct 154 ms 56832 KB Output is correct
32 Correct 179 ms 56884 KB Output is correct
33 Correct 217 ms 57428 KB Output is correct
34 Correct 256 ms 60712 KB Output is correct
35 Correct 271 ms 65940 KB Output is correct
36 Correct 224 ms 60752 KB Output is correct