Submission #1306800

#	Time	Username	Problem	Language	Result	Execution time	Memory
1306800		peteza	Dreaming (IOI13_dreaming)	C++20	0 / 100	1095 ms	13532 KiB

dreaming

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

vector<pair<int, int>> adj[200005];
bool vis[200005];
ll a1[200005], a2[200005];
ll cmin = 0;

pair<ll, int> dfsdep(int x, int p = -1) {
    pair<ll, int> ans(0, x);
    for(auto &e:adj[x]) {
        if(e.first == p) continue;
        auto res = dfsdep(e.first, x);
        res.first += e.second;
        ans = max(ans, res);
    }
    return ans;
}

void dfsfill(int x, int p=-1, ll cd = 0) {
    if(!(~a1[x])) a1[x] = cd;
    else cmin = min(cmin, max(cd, a1[x]));
    for(auto &e:adj[x]) {
        if(e.first == p) continue;
        dfsfill(e.first, x, cd+e.second);
    }
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    for(int i=0;i<M;i++) {
        adj[A[i]].emplace_back(B[i], T[i]);
        adj[B[i]].emplace_back(A[i], T[i]);
    }
    memset(a1, -1, sizeof a1);
    vector<long long> anses;
    ll ans1 = 0;
    for(int i=0;i<N;i++) {
        if(vis[i]) continue;
        int e1 = dfsdep(i).second;
        int e2 = dfsdep(e1).second;
        ans1 = max(ans1, dfsdep(e1).first);
        cmin = LLONG_MAX;
        dfsfill(e1); dfsfill(e2);
        anses.emplace_back(cmin);
    }
    sort(anses.rbegin(), anses.rend());
    //for(auto e:anses) cout << e << ' ';
    return max(ans1, anses.size() > 0 ? max(anses[0] + anses[1] + L, anses.size() > 1 ? anses[1] + anses[2] + 2*L: 0ll): 1ll);
}

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