Submission #1160028

#	Time	Username	Problem	Language	Result	Execution time	Memory
1160028		nhphuc	Factories (JOI14_factories)	C++17	0 / 100	12 ms	18240 KiB

factories

#include <bits/stdc++.h>
#include "factories.h"
using namespace std;

const int N = 500500;
const long long inf = 1e18;

int sub[N], pos[N];
long long dis[N], mn[N];
pair<int, long long> par[N];
vector<int> modify;
vector<pair<int, int>> adj[N];

void dfs (int u, int p = 0, long long dep = 0){
    sub[u] = 1;
    dis[u] = dep;
    for (auto [v, d] : adj[u]){
        if (v != p && pos[v] == 0){
            dfs(v, u, dep + 1ll * d);
            sub[u] += sub[v];
        }
    }
}

int centroid (int u, int p, int n){
    for (auto [v, d] : adj[u]){
        if (v != p && pos[v] == 0 && sub[v] * 2 > n){
            return centroid(v, u, n);
        }
    }
    return u;
}

void buildCentroid (int u, int p){
    pos[u] = 1;
    dfs(u); 
    vector<int> nxt;
    for (auto [v, d] : adj[u]){
        if (pos[v] == 0 && v != p){
            int nr = centroid(v, u, sub[v]);
            par[nr] = {u, dis[nr]};
            nxt.push_back(nr);
        }
    }
    for (int r : nxt){
        // cout << u << " " << r << "\n";
        buildCentroid(r, u);
    }
    return;
}

void Init (int n, int a[], int b[], int d[]){
    fill(mn, mn + N, inf);
    fill(pos, pos + N, 0);
    for (int i = 0; i < n - 1; ++i){
        ++a[i]; ++b[i];
        adj[a[i]].push_back({b[i], d[i]});
        adj[b[i]].push_back({a[i], d[i]});
    }
    dfs(1);
    int root = centroid(1, 0, n);
    buildCentroid(root, root);
    return;
}

void upd (int u, long long dep = 0){
    mn[u] = min(mn[u], dep);
    modify.push_back(u);
    auto [v, d] = par[u];
    if (v != 0){
        upd(v, dep + 1ll * d);
    }
    return;
}

long long get (int u, long long dep = 0){
    long long ans = dep + mn[u];
    auto [v, d] = par[u];
    if (v != 0){
        ans = min(ans, get(v, dep + d));
    }
    return ans;
}

long long Query (int S, int X[], int T, int Y[]){
    modify.clear();
    for (int i = 0; i < S; ++i){
        ++X[i];
        upd(X[i]);
    }
    long long ans = inf;
    for (int i = 0; i < T; ++i){
        ++Y[i];
        ans = min(ans, get(Y[i]));
    }
    for (int u : modify){
        mn[u] = inf;
    }
    return ans;
}

• Subtask 1: 0 / 15
• Subtask 2: 0 / 18
• Subtask 3: 0 / 67