Submission #404844

#	Time	Username	Problem	Language	Result	Execution time	Memory
404844		danielcm585	Dreaming (IOI13_dreaming)	C++14	0 / 100	46 ms	11460 KiB

dreaming

#include "dreaming.h"

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

#define fi first
#define se second

typedef pair<int,int> ii;

vector<int> sz, dep;
vector<vector<ii>> adj;

void dfs(int cur, int par) {
    sz[cur] = 1;
    for (auto nx : adj[cur]) {
        if (nx.fi == par) continue;
        dfs(nx.fi,cur);
        sz[cur] += sz[nx.fi];
    }
}

int maxDist(int cur, int par) {
    int ret = dep[cur];
    for (auto nx : adj[cur]) {
        if (nx.fi == par) continue;
        dep[nx.fi] = dep[cur]+nx.se;
        ret = max(ret,maxDist(nx.fi,cur));
    }
    return ret;
}

int centroid(int cur, int par, int sub) {
    for (auto nx : adj[cur]) {
        if (nx.fi == par) continue;
        if (sz[nx.fi]*2 >= sub) return centroid(nx.fi,cur,sub);
    }
    return cur;
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    adj = vector<vector<ii>>(N);
    for (int i = 0; i < M; i++) {
        adj[A[i]].push_back(ii(B[i],T[i]));
        adj[B[i]].push_back(ii(A[i],T[i]));
    }
    sz = dep = vector<int>(N,0);
    vector<int> tmp;
    for (int i = 0; i < N; i++) {
        if (!sz[i]) {
            dfs(i,-1);
            int cent = centroid(i,-1,sz[i]);
            int maxi = maxDist(cent,-1);
            tmp.push_back(maxi);
        }
    }
    sort(tmp.begin(),tmp.end());
    N = tmp.size();
    vector<int> v(N);
    for (int i = 0, l = (N-1)/2, r = (N-1)/2+1; i < N; i++) {
        if (i&1) v[r++] = tmp.back();
        else v[l--] = tmp.back();
        tmp.pop_back();
    }
    int ans = 0;
    priority_queue<int> pq;
    for (int i = 0; i < N; i++) {
        if (!pq.empty()) ans = max(ans,v[i]+i*L+pq.top());
        pq.push(v[i]-i*L);
    }
    return ans;
}

/*
12 8 2
0 8 4
2 8 2
2 7 4
6 10 3
1 3 1
1 9 5
1 5 7
5 11 3
*/

• Subtask 1: 0 / 14
• Subtask 2: 0 / 10
• Subtask 3: 0 / 23
• Subtask 4: 0 / 18
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23