oj.uz

Submission #382058

# Submission time Handle Problem Language Result Execution time Memory
382058 2021-03-26T10:36:20 Z rocks03 Valley (BOI19_valley) C++14
100 / 100
 227 ms 51692 KB 
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ff first
#define ss second
#define pb push_back
#define SZ(x) ((int)(x).size())
#define all(x) x.begin(), x.end()
#define debug(x) cout << #x << ": " << x << " "
#define nl cout << "\n"
#define rep(i, a, b) for(int i = (a); i < (b); i++)
#define per(i, a, b) for(int i = (a); i >= (b); i--)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

struct Edge{
    int u, w, i;
};
const int MAXN = 2e5+100;
int N, S, Q, E, shop[MAXN];
pii edge[MAXN];
vector<Edge> g[MAXN];

int timer, tin[MAXN], tou[MAXN];

const int MAXK = 20+5;
int depth[MAXN], pa[MAXK][MAXN];
bool is_shop[MAXN];
ll dist[MAXN], min_dist[MAXN], value[MAXN], answer[MAXK][MAXN];

void dfs(int v, int p){
    tin[v] = timer++;
    pa[0][v] = p;
    min_dist[v] = LLONG_MAX;
    if(is_shop[v]) min_dist[v] = dist[v];
    for(auto [u, w, i] : g[v]){
        if(u != p){
            depth[u] = depth[v] + 1;
            dist[u] = dist[v] + w;
            dfs(u, v);
            if(min_dist[u] != LLONG_MAX){
                min_dist[v] = min(min_dist[v], min_dist[u]);
            }
        }
    }
    tou[v] = timer - 1;
    value[v] = LLONG_MAX;
    if(min_dist[v] != LLONG_MAX){
        value[v] = min_dist[v] - 2 * dist[v];
    }
}

bool is_ancestor(int u, int v){
    return (tin[u] <= tin[v] && tou[v] <= tou[u]);
}

void solve(){
    cin >> N >> S >> Q >> E;
    --E;
    rep(i, 0, N - 1){
        int u, v, w;
        cin >> u >> v >> w;
        --u, --v;
        g[u].pb({v, w, i});
        g[v].pb({u, w, i});
        edge[i] = {u, v};
    }
    rep(i, 0, S){
        cin >> shop[i];
        --shop[i];
        is_shop[shop[i]] = true;
    }
    dfs(E, -1);
    rep(v, 0, N){
        if(pa[0][v] == -1){
            answer[0][v] = value[v];
        } else{
            answer[0][v] = min(value[v], value[pa[0][v]]);
        }
    }
    rep(k, 0, MAXK - 1){
        rep(i, 0, N){
            if(pa[k][i] == -1){
                pa[k + 1][i] = -1;
                answer[k + 1][i] = answer[k][i];
            } else{
                pa[k + 1][i] = pa[k][pa[k][i]];
                answer[k + 1][i] = min(answer[k][i], answer[k][pa[k][i]]);
            }
        }
    }
    rep(q, 0, Q){
        int i, x;
        cin >> i >> x;
        --i, --x;
        auto [u, v] = edge[i];
        if(is_ancestor(u, x) && is_ancestor(v, x)){
            int lca = is_ancestor(u, v) ? v : u;
            int diff = depth[x] - depth[lca];
            ll cur = dist[x];
            ll ans = LLONG_MAX;
            if(value[x] != LLONG_MAX) ans = cur + value[x];
            per(k, MAXK - 1, 0){
                if(diff >> k & 1){
                    if(answer[k][x] != LLONG_MAX)
                        ans = min(ans, cur + answer[k][x]);
                    x = pa[k][x];
                }
            }
            if(ans == LLONG_MAX){
                cout << "oo\n";
            } else{
                cout << ans << "\n";
            }
        } else{
            cout << "escaped\n";
        }
    }
}

int main(){
    ios_base::sync_with_stdio(false), cin.tie(nullptr);
    solve();
    return 0;
}

Compilation message

valley.cpp: In function 'void dfs(int, int)':
valley.cpp:37:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   37 |     for(auto [u, w, i] : g[v]){
      |              ^
valley.cpp: In function 'void solve()':
valley.cpp:97:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   97 |         auto [u, v] = edge[i];
      |              ^

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5484 KB Output is correct
2 Correct 8 ms 5484 KB Output is correct
3 Correct 7 ms 5484 KB Output is correct
4 Correct 8 ms 5484 KB Output is correct

Subtask #2
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5484 KB Output is correct
2 Correct 8 ms 5484 KB Output is correct
3 Correct 7 ms 5484 KB Output is correct
4 Correct 8 ms 5484 KB Output is correct
5 Correct 5 ms 5868 KB Output is correct
6 Correct 5 ms 5740 KB Output is correct
7 Correct 5 ms 5868 KB Output is correct
8 Correct 5 ms 5868 KB Output is correct
9 Correct 5 ms 5740 KB Output is correct
10 Correct 6 ms 5868 KB Output is correct
11 Correct 6 ms 5868 KB Output is correct
12 Correct 5 ms 5740 KB Output is correct
13 Correct 6 ms 5868 KB Output is correct
14 Correct 5 ms 5868 KB Output is correct

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 156 ms 44600 KB Output is correct
2 Correct 160 ms 44268 KB Output is correct
3 Correct 176 ms 44140 KB Output is correct
4 Correct 192 ms 45932 KB Output is correct
5 Correct 165 ms 46060 KB Output is correct
6 Correct 219 ms 47596 KB Output is correct

Subtask #4
41.0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5484 KB Output is correct
2 Correct 8 ms 5484 KB Output is correct
3 Correct 7 ms 5484 KB Output is correct
4 Correct 8 ms 5484 KB Output is correct
5 Correct 5 ms 5868 KB Output is correct
6 Correct 5 ms 5740 KB Output is correct
7 Correct 5 ms 5868 KB Output is correct
8 Correct 5 ms 5868 KB Output is correct
9 Correct 5 ms 5740 KB Output is correct
10 Correct 6 ms 5868 KB Output is correct
11 Correct 6 ms 5868 KB Output is correct
12 Correct 5 ms 5740 KB Output is correct
13 Correct 6 ms 5868 KB Output is correct
14 Correct 5 ms 5868 KB Output is correct
15 Correct 156 ms 44600 KB Output is correct
16 Correct 160 ms 44268 KB Output is correct
17 Correct 176 ms 44140 KB Output is correct
18 Correct 192 ms 45932 KB Output is correct
19 Correct 165 ms 46060 KB Output is correct
20 Correct 219 ms 47596 KB Output is correct
21 Correct 138 ms 45164 KB Output is correct
22 Correct 157 ms 47212 KB Output is correct
23 Correct 180 ms 46956 KB Output is correct
24 Correct 186 ms 48964 KB Output is correct
25 Correct 181 ms 51692 KB Output is correct
26 Correct 143 ms 47596 KB Output is correct
27 Correct 144 ms 47212 KB Output is correct
28 Correct 173 ms 47084 KB Output is correct
29 Correct 180 ms 48364 KB Output is correct
30 Correct 227 ms 49900 KB Output is correct
31 Correct 140 ms 47724 KB Output is correct
32 Correct 152 ms 47340 KB Output is correct
33 Correct 162 ms 47340 KB Output is correct
34 Correct 188 ms 49004 KB Output is correct
35 Correct 193 ms 51692 KB Output is correct
36 Correct 192 ms 49516 KB Output is correct