제출 #366873

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
366873		ACmachine	Valley (BOI19_valley)	C++17	100 / 100	454 ms	47340 KiB

valley

#include <bits/stdc++.h>
using namespace std;
 
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
 
template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
 
typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str;
 
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
 
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<str> vstr;
 
#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back 
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define rsz resize 
#define MANY_TESTS int tcase; cin >> tcase; while(tcase--)
	
const double EPS = 1e-9;
const int MOD = 1e9+7; // 998244353;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};
 
#ifdef DEBUG
#define DBG if(1)
#else
#define DBG if(0)
#endif
 
#define dbg(x) cout << "(" << #x << " : " << x << ")" << endl;
// ostreams
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "[";  REP(i, v.size()) out << v[i] << ", ";  out << "]"; return out;}
// istreams
template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }
template<class T, class U>
istream& operator>>(istream& in, pair<T, U> &p){ in >> p.ff >> p.ss; return in; }
//searches
template<typename T, typename U>
T bsl(T lo, T hi, U f){ hi++; T mid; while(lo < hi){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid+1; } return lo; }
template<typename U>
double bsld(double lo, double hi, U f, double p = 1e-9){ int r = 3 + (int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid; } return (lo + hi)/2; }
template<typename T, typename U>
T bsh(T lo, T hi, U f){ lo--; T mid; while(lo < hi){ mid = (lo + hi + 1)/2; f(mid) ? lo = mid : hi = mid-1; } return lo; }
template<typename U>
double bshd(double lo, double hi, U f, double p = 1e-9){ int r = 3+(int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? lo = mid : hi = mid; } return (lo + hi)/2; }
// some more utility functions
template<typename T>
pair<T, int> get_min(vector<T> &v){ typename vector<T> :: iterator it = min_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T>
pair<T, int> get_max(vector<T> &v){ typename vector<T> :: iterator it = max_element(v.begin(), v.end()); return mp(*it, it - v.begin());}        
template<typename T> bool ckmin(T& a, const T& b){return b < a ? a = b , true : false;}
template<typename T> bool ckmax(T& a, const T& b){return b > a ? a = b, true : false;}
 
    
int main(){
 	ios_base::sync_with_stdio(false);
 	cin.tie(NULL); cout.tie(NULL);
	int n, s, q, e;
    cin >> n >> s >> q >> e;
    e--; 
    vector<vector<array<int, 2>>> g(n);
    vector<array<int, 2>> edges(n - 1);
    REP(i, n - 1){
        int a, b, w;
        cin >> a >> b >> w;
        a--; b--;
        g[a].pb({b, w});
        g[b].pb({a, w});
        edges[i] = {a, b};
    }
    vector<bool> is_shop(n, false);
    REP(i, s){
        int x; cin >> x;
        x--;
        is_shop[x] = true;
    }
    vll opt(n, INFF);
    function<void(int, int)> calc_opt = [&](int v, int p){
        for(auto x : g[v]){
            if(x[0] == p) continue;
            calc_opt(x[0], v);
        }
        if(is_shop[v]) opt[v] = 0;
        for(auto x : g[v]){
            if(x[0] == p) continue;
            opt[v] = min(opt[v], opt[x[0]] + x[1]);
        }
    };
    calc_opt(e, -1);
    vi lev(n, 0);
    vll dist(n, 0);
    const int mxn = 20;
    vector<vi> nxt(n, vi(mxn, -1));
    vector<vll> nxt_values(n, vll(mxn, INFF));
    function<void(int, int)> dfs = [&](int v, int p){
        nxt[v][0] = p;
        if(p != -1)
            nxt_values[v][0] = opt[v] - dist[v];
        FOR(i, 1, mxn, 1){
            if(nxt[v][i - 1] != -1){
                nxt[v][i] = nxt[nxt[v][i - 1]][i - 1]; 
                nxt_values[v][i] = min(nxt_values[v][i - 1], nxt_values[nxt[v][i - 1]][i - 1]);
            }
        }
        for(auto x : g[v]){
            if(x[0] == p) continue;
            dist[x[0]] = dist[v] + x[1];
            lev[x[0]] = lev[v] + 1;
            dfs(x[0], v);
        }
    };
    dfs(e, -1);
    REP(qq, q){
        int i, r; 
        cin >> i >> r;
        i--; r--;
        int u = edges[i][0]; 
        int v = edges[i][1];
        if(lev[u] < lev[v]) swap(u, v);
        int X = r;
        REPD(j, 19){
            if(lev[X] - (1 << j) >= lev[u]){
                X = nxt[X][j];
            }
        }
        if(X != u){
            cout << "escaped" << "\n";
            continue;
        }
        // now u is ancestor of r;
        // use precomputed binlifts of value opt[x] - dist(E, x);
        X = r;
        ll ans = INFF;
        REPD(j, 19){
            if(lev[X] - (1 << j) >= lev[u]){
                ans = min(ans, nxt_values[X][j] + dist[r]);
                X = nxt[X][j]; 
            }
        }
        ans = min(ans, nxt_values[X][0] + dist[r]);
        if(ans == INFF){
            cout << "oo" << "\n";
        }
        else{
            cout << ans << "\n";
        }
    }
    return 0;
}

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