Submission #1253952

#	Time	Username	Problem	Language	Result	Execution time	Memory
1253952		farica	Factories (JOI14_factories)	C++20	0 / 100	4 ms	832 KiB

factories

#include "factories.h"
#include<bits/stdc++.h>
using namespace std;
using vi = vector<int>;
using pi = pair<int,int>;
using ll = long long;

vector<vector<pi>>adjL;
vector<vector<pair<ll,ll>>>ancestors;
vi sz;
vector<bool>is_removed;
int N2;

int get_sz(int pos, int prev = -1) {
    sz[pos] = 1;
    for(pi adj: adjL[pos]) {
        if(adj.first == prev or is_removed[adj.first]) continue;
        sz[pos] += get_sz(adj.first, pos);
    }
    return sz[pos];
}

int get_centroid(int pos, int n, int prev = -1) {
    for(pi adj: adjL[pos]) {
        if(adj.first == prev or is_removed[adj.first]) continue;
        if(sz[adj.first]*2 > n) return get_centroid(adj.first, n, pos);
    }
    return pos;
}

void get_dists(int pos, int centroid, int prev, ll cur_dist) {
    for(pi adj: adjL[pos]) {
        if(adj.first == prev or is_removed[adj.first]) continue;
        get_dists(adj.first, centroid, pos, cur_dist + adj.second);
    }
    ancestors[pos].push_back({centroid, cur_dist});
}

void build(int pos = 0) {
    int centroid = get_centroid(pos, get_sz(pos));
    for(pi adj: adjL[centroid]) {
        if(is_removed[adj.first]) continue;
        get_dists(adj.first, centroid, centroid, adj.second);
    }
    is_removed[centroid] = 1;
    for(pi adj: adjL[centroid]) {
        if(is_removed[adj.first]) continue;
        build(adj.first);
    }
}

void Init(int N, int A[], int B[], int D[]) {
    N2 = N;
    adjL.assign(N, vector<pi>());
    is_removed.assign(N, 0);
    ancestors.assign(N, vector<pair<ll,ll>>());
    sz.assign(N, 0);
    for(int i=0; i<N-1; ++i) {
        adjL[A[i]].push_back({B[i], D[i]});
        adjL[B[i]].push_back({A[i], D[i]});
    }
    build();
}

const ll MXVAL = 1e18;
        
long long Query(int S, int X[], int T, int Y[]) {
    vector<ll> min_dist(N2, MXVAL);
    for(int i=0; i<S; ++i) {
        for(auto &[ancestor, dist]: ancestors[X[i]]) {
            min_dist[ancestor] = min(min_dist[ancestor], dist);
        }
    }
    ll ans = MXVAL;
    for(int i=0; i<T; ++i) {
        for(auto &[ancestor, dist]: ancestors[Y[i]]) {
            if(min_dist[ancestor] == MXVAL) continue;
            ans = min(ans, dist + min_dist[ancestor]);
        }
    }
    return ans;
}

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