Submission #1094893

#	Time	Username	Problem	Language	Result	Execution time	Memory
1094893		Tymond	Valley (BOI19_valley)	C++17	100 / 100	99 ms	43200 KiB

valley

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::steady_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
 
struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }
 
    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

const ll INF = 1e18;
const int MAXN = 1e5 + 7;
const int MAXK = 20;
int jump[MAXK][MAXN];
ll mn[MAXK][MAXN];
int parent[MAXN];
vector<pii> g[MAXN];
pii range[MAXN];
ll dist[MAXN];
int up[MAXN];
int dep[MAXN];
int f[MAXN];
ll len[MAXN];
int n, s, q, source;
int t;
vector<pii> edges;

void dfs(int v, int p, int d, ll x){
    dep[v] = d;
    parent[v] = p;
    len[v] = x;
    range[v].fi = t++;
    if(f[v]){
        dist[v] = 0LL;
    }else{
        dist[v] = INF;
    }

    for(auto [u, c] : g[v]){
        if(u == p){
            continue;
        }
        up[u] = c;
        dfs(u, v, d + 1, (ll)x + c);
        dist[v] = min(dist[v], (ll)dist[u] + c);
    }
    range[v].se = t++;
}

void init(){
    for(int i = 1; i <= n; i++){
        jump[0][i] = parent[i];
        mn[0][i] = (ll)dist[i] - len[i];
    }

    for(int j = 1; j < MAXK; j++){
        for(int i = 1; i <= n; i++){
            jump[j][i] = jump[j - 1][jump[j - 1][i]];
            mn[j][i] = min(mn[j - 1][i], mn[j - 1][jump[j - 1][i]]);
        }
    }
}

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

    cin >> n >> s >> q >> source;
    for(int i = 1; i < n; i++){
        int u, v, c;
        cin >> u >> v >> c;
        g[u].pb({v, c});
        g[v].pb({u, c});
        edges.pb({u, v});
    }

    for(int i = 1; i <= s; i++){
        int v;
        cin >> v;
        f[v] = 1;
    }
    t = 0;
    dfs(source, source, 0, 0LL);

    init();

    while(q--){
        int ind, v;
        cin >> ind >> v;
        ind--;

        int u = edges[ind].fi;
        if(dep[edges[ind].se] > dep[u]){
            u = edges[ind].se;
        }

        if(range[u].fi > range[v].fi || range[v].se > range[u].se){
            cout << "escaped\n";
            continue;
        }

        if(dist[u] == INF){
            cout << "oo\n";
            continue;
        }

        ll ans = dist[v];
        int akt = v;
        for(int j = MAXK - 1; j >= 0; j--){
            if(dep[akt] - (1 << j) > dep[u]){
                ans = min(ans, (ll)mn[j][akt] + len[v]);
                akt = jump[j][akt];
            }
        }
        ans = min(ans, (ll)dist[akt] - len[akt] + len[v]);
        ans = min(ans, (ll)dist[u] - len[u] + len[v]);
        cout << ans << '\n';
    }

    return 0;
}

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