Submission #875552

#	Time	Username	Problem	Language	Result	Execution time	Memory
875552		hmm789	Dreaming (IOI13_dreaming)	C++14	100 / 100	45 ms	16704 KiB

dreaming

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

int dist[100000], prv[100000], idx;
vector<pair<int, int>> adj[100000];
vector<int> v, diam, path, tmp;
void dfs(int x, int p) {
    if(dist[x] > dist[idx]) idx = x;
    tmp.push_back(x);
    prv[x] = p;
    for(auto i : adj[x]) if(i.first != p) {
        if(dist[i.first] == -1) {
            dist[i.first] = dist[x]+i.second;
            dfs(i.first, x);
        }
    }
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    for(int i = 0; i < M; i++) {
        adj[A[i]].push_back({B[i], T[i]});
        adj[B[i]].push_back({A[i], T[i]});
    }
    memset(dist, -1, sizeof(dist));
    for(int i = 0; i < N; i++) {
        if(dist[i] != -1) continue;
        idx = i;
        dist[i] = 0;
        dfs(i, -1);
        while(tmp.size()) {
            dist[tmp.back()] = -1;
            tmp.pop_back();
        }
        dist[idx] = 0;
        dfs(idx, -1);
        tmp.clear();
        int cur = (int)1e9;
        for(int j = idx; j != -1; j = prv[j]) path.push_back(j);
        for(int j : path) cur = min(cur, max(dist[j], dist[idx]-dist[j]));
        v.push_back(cur);
        diam.push_back(dist[idx]);
        path.clear();
    }
    sort(v.begin(), v.end(), greater<int>());
    sort(diam.begin(), diam.end(), greater<int>());
    if(v.size() == 1) return diam[0];
    if(v.size() == 2) return max(diam[0], v[0]+v[1]+L);
    return max(diam[0], max(v[0]+v[1]+L, v[1]+v[2]+2*L));
}

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