Submission #780083

#	Time	Username	Problem	Language	Result	Execution time	Memory
780083		Cookie	Valley (BOI19_valley)	C++14	100 / 100	177 ms	55424 KiB

valley

#include<bits/stdc++.h>
#include<fstream>
using namespace std;
ifstream fin("VNOICUP.INP");
ofstream fout("VNOICUP.OUT");
#define sz(a) (int)a.size()
#define ll long long
#define pb push_back
#define forr(i, a, b) for(int i = a; i < b; i++)
#define dorr(i, a, b) for(int i = a; i >= b; i--)
#define ld long double
#define vt vector
#include<fstream>
#define fi first
#define se second
#define pll pair<ll, ll>
#define pii pair<int, int>
const ld PI = 3.14159265359;
using u128 = __uint128_t;
//const int x[4] = {1, -1, 0, 0};
//const int y[4] = {0, 0, 1, -1};
const ll mod = 998244353;
const int mxn = 3e5 + 5, mxq = 2e5 + 5, sq = 400, mxv = 2e7 + 5;
//const int base = (1 << 18);
const ll inf = 1e15, neg = -69420;

int n, q, s, e;
vt<pll>adj[mxn + 1];
ll dep[mxn + 1], tin[mxn + 1], tout[mxn + 1], tt = 0, dp[mxn + 1];
bool ok[mxn + 1];
ll up[mxn + 1][18], mn[mxn + 1][18], h[mxn + 1];
vt<pii>edge;
void dfs(int u, int pre, ll d){
    tin[u] = ++tt; dep[u] = d; 
    if(ok[u])dp[u] = d;
    else dp[u] = inf;
    for(auto [v, w]: adj[u]){
        if(v != pre){
            up[v][0] = u; h[v] = h[u] + 1;
            dfs(v, u, d + w); 
            dp[u] = min(dp[u], dp[v]);
        }
    }
    tout[u] = tt;
}
bool inside(int u, int r){
    return(tin[u] <= tin[r] && tout[r] <= tout[u]);
}
signed main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> n >> s >> q >> e;
    for(int i = 1; i <= n; i++){
        for(int j = 0; j < 17; j++){
            mn[i][j] = inf;
        }
    }
    forr(i, 1, n){
        int u, v, w; cin >> u >> v >> w;
        adj[u].pb({v, w}); adj[v].pb({u, w});
        edge.pb({u, v});
    }
    for(int i = 0; i < s; i++){
        int x; cin >> x; ok[x] = 1;
    }
    dfs(e, -1, 0);

    for(int i = 1; i <= n; i++){
        if(dp[i] != inf)dp[i] -= 2 * dep[i]; 
        mn[i][0] = dp[i];
    }
    for(int i = 1; i < 17; i++){
        for(int j = 1; j <= n; j++){
            up[j][i] = up[up[j][i - 1]][i - 1];
            mn[j][i] = min(mn[j][i - 1], mn[up[j][i - 1]][i - 1]);
        }
    }
    
    for(int i = 0; i < q; i++){
        int id, r; cin >> id >> r; --id;
        auto [u, v] = edge[id];
        if(dep[u] < dep[v])swap(u, v);
        // is r inside subtree of u
        if(!inside(u, r)){
            cout << "escaped" << "\n";
        }else{
            int dif = h[r] - h[u] + 1;
            ll res = inf, val = dep[r];
            for(int j = 0; j < 17; j++){
                if(dif & (1 << j)){
                    res = min(res, mn[r][j]); r = up[r][j];
                }
            }
            if(res >= inf)cout << "oo" << "\n";
            else cout << res + val << "\n";
        }
    }
    
    return(0);
}

Compilation message (stderr)

valley.cpp: In function 'void dfs(int, int, long long int)':
valley.cpp:37:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   37 |     for(auto [v, w]: adj[u]){
      |              ^
valley.cpp: In function 'int main()':
valley.cpp:80:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   80 |         auto [u, v] = edge[id];
      |              ^

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