Submission #382006

#	Time	Username	Problem	Language	Result	Execution time	Memory
382006		rocks03	Valley (BOI19_valley)	C++14	59 / 100	3080 ms	14980 KiB

valley

#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];

void dijkstra(int s, int ind){
    vector<ll> d(N, LLONG_MAX);
    d[s] = 0;
    priority_queue<pll, vector<pll>, greater<pll>> pq;
    pq.push({d[s], s});
    while(!pq.empty()){
        auto [dist, v] = pq.top();
        pq.pop();
        if(dist > d[v]) continue;
        for(auto [u, w, i] : g[v]){
            if(i == ind) continue;
            if(d[u] > d[v] + w){
                d[u] = d[v] + w;
                pq.push({d[u], u});
            }
        }
    }
    if(d[E] != LLONG_MAX){
        cout << "escaped\n";
    } else{
        ll ans = LLONG_MAX;
        rep(i, 0, S){
            ans = min(ans, d[shop[i]]);
        }
        if(ans != LLONG_MAX){
            cout << ans << "\n";
        } else{
            cout << "oo\n";
        }
    }
}

int timer, tin[MAXN], tou[MAXN];
void dfs(int v, int p){
    tin[v] = timer++;
    for(auto [u, w, i] : g[v]){
        if(u != p){
            dfs(u, v);
        }
    }
    tou[v] = timer - 1;
}
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];
    }
    if(S == N){
        dfs(E, -1);
        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)){
                cout << "0\n";                
            } else{
                cout << "escaped\n";
            }
        }
        return;
    }
    rep(q, 0, Q){
        int i, v;
        cin >> i >> v;
        --i, --v;
        dijkstra(v, i);
    }
}

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

Compilation message (stderr)

valley.cpp: In function 'void dijkstra(int, int)':
valley.cpp:31:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   31 |         auto [dist, v] = pq.top();
      |              ^
valley.cpp:34:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   34 |         for(auto [u, w, i] : g[v]){
      |                  ^
valley.cpp: In function 'void dfs(int, int)':
valley.cpp:60:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   60 |     for(auto [u, w, i] : g[v]){
      |              ^
valley.cpp: In function 'void solve()':
valley.cpp:92:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   92 |             auto [u, v] = edge[i];
      |                  ^

• Subtask 1: 9 / 9
• Subtask 2: 27 / 27
• Subtask 3: 23 / 23
• Subtask 4: 0 / 41