Submission #476218

#	Time	Username	Problem	Language	Result	Execution time	Memory
476218		Karliver	Valley (BOI19_valley)	C++17	100 / 100	267 ms	47896 KiB

valley

    
#include <bits/stdc++.h>

#define FIXED_FLOAT(x)  std::fixed <<std::setprecision(20) << (x)
#define all(v) (v).begin(), (v).end()
using namespace  std;
#define forn(i,n) for (int i = 0; i < (n); ++i)
#define rforn(i, n) for(int i = (n) - 1;i >= 0;--i)
using ll = long long;
int mod = (ll)1e9 + 7;
#define PI acos(-1)
typedef pair<int, int> pairs;

const int INF = 1e9 + 1;
const int N = 2e5 + 100;
const double eps = 1e-7;
const ll inf = 1e17;
template <class T> using V = vector<T>;  
template <class T> using VV = V<V<T>>;  

template <typename XPAX>
void ckma(XPAX &x, XPAX y) {
    x = (x < y ? y : x);
}
template <typename XPAX>
void ckmi(XPAX &x, XPAX y) {
    x = (x > y ? y : x);
}
void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
VV<pairs> g(N);
int F[N][20];
ll dis[N][20];
V<bool> shop(N, false);
V<ll> ms(N);
V<int> dep(N, 0);
int T = 0;
V<array<int, 2>> D(N);
V<int> tin(N), tout(N);
V<ll> ts(N);
void dfs1(int v, int p) {
    tin[v] = ++T;
    F[v][0] = p;
    for(int i = 1;i < 20;++i)
        F[v][i] = F[F[v][i - 1]][i - 1];
    for(auto [c,w] : g[v])
        if(c != p) {
            ts[c] = ts[v] + w;
            dep[c] = dep[v] + 1;
            dfs1(c, v);
            
        }

    tout[v] = T;
}
void dfs2(int v, int p) {
    if(shop[v])
        ms[v] = ts[v];
    else ms[v] = inf;

    for(auto [c, w] : g[v]) {
        if(c == p)continue;
        dfs2(c, v);
        ckmi(ms[v], ms[c]);
    }
}

void dfs3(int v, int p, int cost) {
    dis[v][0] = ms[v];
    for(int i = 1;i < 20;++i) {
        dis[v][i] = min(dis[v][i - 1], dis[F[v][i - 1]][i - 1]);
    }
    for(auto [c, w] : g[v])
        if(c != p)dfs3(c, v, w);
}
bool isb(int x, int y) {
    return tin[x] <= tin[y] && tout[y] <= tout[x];
}
ll jp(int x, int k) {
    ll ret = inf;

    rforn(j, 20) if(k >> j & 1) {
        ckmi(ret, dis[x][j]);
        x = F[x][j];
    }
    return ret;
}

void solve() {


    int n, s, q, e;

    cin >> n >> s >> q >> e;

    
    for(int i = 1;i <= n - 1;++i) {
        int a, b, c;
        cin >> a >> b >> c;
        g[a].push_back({b, c});
        g[b].push_back({a, c});
        D[i] = {a, b};
    }
    forn(i, s) {
        int x;
        cin >> x;
        shop[x] = 1;
    }
    
    dfs1(e, e);

    dfs2(e, e);

    for(int i = 1;i <= n;++i) ms[i] -= 2 * ts[i];

    dfs3(e, e, 0);

    //debug(dis[9][1]);

    while(q--) {
        int id, R;
        cin >> id >> R;
        int x = D[id][0], y = D[id][1];
        if(!isb(x, R) || !isb(y, R)) {
            cout << "escaped" << '\n';
            continue;
        }
        if(tin[x] < tin[y])swap(x, y);
        int k = dep[R] - dep[x] + 1;
        assert(k >= 0);
        ll res = jp(R, k) + ts[R];
        if(res < (ll)1e16)cout << res<< '\n';
        else cout << "oo" << '\n';
    }


}
void test_case() {
    int t;
    cin >> t;
    forn(p, t) {

        //cout << "Case #" << p + 1 << ": ";
        solve();
    }
}
int main() {

    ios::sync_with_stdio(false);
    cin.tie(0);

    solve();

}

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