Submission #713022

#	Time	Username	Problem	Language	Result	Execution time	Memory
713022		thimote75	Dreaming (IOI13_dreaming)	C++14	18 / 100	49 ms	15052 KiB

dreaming

#include "dreaming.h"
#include <bits/stdc++.h>

using namespace std;

#define num long long
#define next first
#define cost second
#define t_road pair<int, num>
#define t_roads vector<t_road>
#define graph vector<t_roads>
#define ndata vector<num>

graph roads;

// here, max is refered as the first maximal
// mix is refered as the second maximal
ndata max_diameter;
ndata mix_diameter;
ndata depth;

ndata visit_id; num stage = 0;

void replace (int node, num nw_d) {
    if (nw_d >= max_diameter[node]) {
        mix_diameter[node] = max_diameter[node];
        max_diameter[node] = nw_d;
    } else if (mix_diameter[node] < nw_d)
        mix_diameter[node] = nw_d;
}
num get (int node, int nxt, num cst) {
    if (max_diameter[node] == max_diameter[nxt] + cst) return mix_diameter[node];
    return max_diameter[node];
}

num dfs_diam (int node, int parent, num local_depth) {
    max_diameter[node] = 0;
    mix_diameter[node] = 0;
    visit_id[node] = stage;

    depth[node] = local_depth;

    for (t_road road : roads[node]) {
        if (parent == road.next) continue ;

        int nw_d = dfs_diam(road.next, node, local_depth + road.cost) - local_depth;
        replace(node, nw_d);
    }

    return max_diameter[node] + local_depth;
}
void dfs_replace (int node, int parent, num max_depth) {
    replace(node, max_depth);
    visit_id[node] = stage;

    for (t_road road : roads[node]) {
        if (parent == road.next) continue ;

        dfs_replace(road.next, node, road.cost + get(node, road.next, road.cost));
    }
}
num min_component (int node, int parent) {
    num val = max_diameter[node];
    visit_id[node] = stage;

    for (t_road road : roads[node]) {
        if (parent == road.next) continue ;

        val = min(val, min_component(road.next, node));
    }

    return val;
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    roads.resize(N);
    max_diameter.resize(N, -1);
    mix_diameter.resize(N, -1);
    depth.resize(N, -1);
    visit_id.resize(N, -1);
    for (int i = 0; i < M; i ++) {
        roads[A[i]].push_back({ B[i], T[i] });
        roads[B[i]].push_back({ A[i], T[i] });
    }

    for (int i = 0; i < N; i ++)
        if (visit_id[i] != stage)
            dfs_diam(i, -1, 0);
    stage ++;
    for (int i = 0; i < N; i ++)
        if (visit_id[i] != stage)
            dfs_replace(i, -1, 0);
    stage ++;
    
    vector<num> values;
    for (int i = 0; i < N; i ++)
        if (visit_id[i] != stage)
            values.push_back( min_component(i, -1) );
    stage ++;
    
    sort(values.rbegin(), values.rend());
    if (values.size() == 1) return values[0];
    if (values.size() == 2) return values[0] + values[1] + L;

    return L + values[1] + max(values[0], values[2] + L);
}

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