Submission #559930

#	Time	Username	Problem	Language	Result	Execution time	Memory
559930		tamthegod	Valley (BOI19_valley)	C++14	0 / 100	779 ms	122028 KiB

valley

#include<iostream>
#include<iomanip>
#include<algorithm>
#include<stack>
#include<queue>
#include<string>
#include<string.h>
#include<cmath>
#include<vector>
#include<map>
#include<unordered_map>
#include<set>
#include<unordered_set>
#include<cstdio>
#include<bitset>
#include<chrono>
#include<random>
#include<ext/rope>
/* ordered_set
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
*/
#define int long long
#define pb push_back
#define fi first
#define se second
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int maxN = 1e6 + 5;
const int mod = 1e9 + 7;
const ll oo = 1e17;
int n, s, Q, e;
int vis[maxN], parCent[maxN], dp[maxN];
vector<int> adj[maxN];
bool is_shop[maxN];
map<pair<int, int>, int> id, dist;
int depth[maxN], lg[maxN];
int f[maxN][21];
int w[maxN], ans[maxN];
pair<int, int> edge[maxN];
struct TQuery
{
    int r, id;
};
int res[maxN];
vector<TQuery> q[maxN];
void Log()
{
    for(int i=2; i<maxN; i++)
        lg[i] = lg[i / 2] + 1;
}
void predfs(int u, int par)
{
    for(int v : adj[u])
    {
        if(v == par)
            continue;
        depth[v] = depth[u] + 1;
        f[v][0] = u;
        w[v] = w[u] + dist[ {u, v}];
        for(int i=1; i<=lg[n]; i++)
            f[v][i] = f[f[v][i - 1]][i - 1];
        predfs(v, u);
    }
}
int lca(int u, int v)
{
    if(depth[u] < depth[v])
        swap(u, v);
    int k = depth[u] - depth[v];
    for(int i = lg[n]; i >= 0; --i)
        if(k & (1 << i))
        {
            u = f[u][i];
            k -= 1 << i;
        }
    if(u == v)
        return u;
    for(int i = lg[n]; i >= 0; --i)
        if(f[u][i] != f[v][i])
        {
            u = f[u][i];
            v = f[v][i];
        }
    return f[u][0];
}
int Dist(int u, int v)
{
    return w[u] + w[v] - 2 * w[lca(u, v)];
}
int dfs(int u, int par)
{
    dp[u] = 1;
    for(int v : adj[u])
    {
        if(v == par || vis[v])
            continue;
        dp[u] += dfs(v, u);
    }
    return dp[u];
}
int Find_Centroid(int u, int par, int sz)
{
    for(int v : adj[u])
    {
        if(v == par || vis[v])
            continue;
        if(dp[v] > sz / 2)
            return Find_Centroid(v, u, sz);
    }
    return u;
}
int Decompose(int u)
{
    int root = Find_Centroid(u, 0, dfs(u, 0));
    vis[root] = 1;
    for(int v : adj[root])
    {
        if(vis[v])
            continue;
        parCent[Decompose(v)] = root;
    }
    return root;
}
bool Inside(int u, int v, int i)
{
    int t = lca(u, v);
    if(lca(u, i) == i && lca(i, t) == t)
        return true;
    if(lca(v, i) == i && lca(i, t) == t)
        return true;
    return false;
}
void update(int u)
{
    for(int v=u; v; v=parCent[v])
        ans[v] = min(ans[v], Dist(u, v));
}
int get(int u, int id)
{
    int t1 = edge[id].fi, t2 = edge[id].se;
    int res = oo;
    for(int v=u; v; v=parCent[v])
    {
        if(!Inside(u, v, t1) || !Inside(u, v, t2))
            res = min(res, ans[v] + Dist(u, v));
    }
    return res;
}
void DFS(int u, int par)
{
    if(is_shop[u])
        update(u);
    int pos = id[ {u, par}];
    for(int v : adj[u])
    {
        if(v == par)
            continue;
        DFS(v, u);
    }
    for(TQuery a : q[pos])
    {
        if(!Inside(a.r, e, u) || !Inside(a.r, e, par))
        {
            //    cout << a.r << " " << e << '\n';
            res[a.id] = -1;
            continue;
        }
        res[a.id] = get(a.r, pos);
    }
}
void ReadInput()
{
    cin >> n >> s >> Q >> e;
    for(int i=1; i<n; i++)
    {
        int u, v, w;
        cin >> u >> v >> w;
        edge[i] = {u, v};
        adj[u].pb(v);
        adj[v].pb(u);
        dist[ {u, v}] = dist[ {v, u}] = w;
        id[ {u, v}] = id[ {v, u}] = i;
    }
    for(int i=1; i<=s; i++)
    {
        int x;
        cin >> x;
        is_shop[x] = 1;
    }
    for(int i=1; i<=Q; i++)
    {
        int id, r;
        cin >> id >> r;
        q[id].pb({r, i});
    }
}
void Solve()
{
    predfs(Decompose(1), 0);
    memset(ans, 37, sizeof ans);
    DFS(1, 0);
//   cout << e;return;
    for(int i=1; i<=Q; i++)
    {
        if(res[i] == -1)
            cout << "escaped\n";
        else if(res[i] >= oo)
            cout << "oo\n";
        else
            cout << res[i] << '\n';
    }
}
int32_t main()
{
    //freopen("x.inp", "r", stdin);
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    Log();
    ReadInput();
    Solve();
}

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