Submission #679316

#	Time	Username	Problem	Language	Result	Execution time	Memory
679316		kusssso	Dreaming (IOI13_dreaming)	C++17	100 / 100	86 ms	16180 KiB

dreaming

#include<bits/stdc++.h>
#include "dreaming.h"
using namespace std;
using ll = long long;
const int N = 1e5 + 5;
#define fi first
#define se second

vector<int> Tree;
int d[N];
bool used[N];
int pa[N];

vector<pair<int, int>> g[N];

void dfs (int u, int p) {
    Tree.push_back(u);
    used[u] = 1;
    pa[u] = p;
    for (auto& e : g[u]) {
        int v = e.fi;
        int w = e.se;
        if (v != p) {
            d[v] = d[u] + w;
            dfs(v, u);
        }
    }
}

// int travelTime (int n, int m, int L, vector<int> A, vector<int> B, vector<int> T) {
    
int travelTime (int n, int m, int L, int A[], int B[], int T[]) {
    for (int i = 0; i < m; i++) {
        g[A[i]].push_back({B[i], T[i]});
        g[B[i]].push_back({A[i], T[i]});
    }
    int longest = 0;
    vector<int> R;
    for (int i = 0; i < n; i++) {
        if (!used[i]) {
            dfs(i, -1);
            int v = i;
            for (auto& j : Tree) if (d[j] > d[v]) v = j;
            Tree.clear();
            d[v] = 0;
            dfs(v, -1);
            for (auto &j : Tree) if (d[j] > d[v]) v = j;
            int u = v;
            int x = v;
            while (u != -1) {
                if (abs(2 * d[u] - d[v]) < abs(2 * d[x] - d[v])) {
                    x = u;
                }
                u = pa[u];
            }
            longest = max(longest, d[v]);
            R.push_back(max(d[x], d[v] - d[x]));
            Tree.clear();
        }
    }
    sort(R.rbegin(), R.rend());
    if (R.size() > 1) {
        longest = max(longest, R[0] + R[1] + L);
        if (R.size() > 2) {
            longest = max(longest, R[1] + R[2] + L * 2);
        }
    }
    return longest;
}

// signed main() {
    // ios_base::sync_with_stdio(0);
    // cin.tie(0);
//     
    // int n, m, L;
    // cin >> n >> m >> L;
    // vector<int> A(m), B(m), T(m);
    // for (int i = 0; i < m; i++) cin >> A[i] >> B[i] >> T[i];
//     
    // cout << travelTime(n,m,L,A,B,T);
//     
    // return 0;
// }

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