Submission #679323

#	Time	Username	Problem	Language	Result	Execution time	Memory
679323		kusssso	Dreaming (IOI13_dreaming)	C++17	14 / 100	58 ms	14328 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;
    int mxrad = 0;
    int root = -1;
    vector<int> center;
    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];
            }
            if (mxrad < max(d[x], d[v] - d[x])) {
                mxrad = max(d[x], d[v] - d[x]);
                root = x;
            }
            center.push_back(x);
            longest = max(longest, d[v]);
            Tree.clear();
        }
    }
    for (int i = 0; i < center.size(); i++) {
        if (center[i] != root) {
            g[root].push_back({center[i], L});
            g[center[i]].push_back({root, L});
        }
    }
    dfs(0, -1);
    int v = 0;
    for (auto &j : Tree) if (d[j] > d[v]) v = j;
    d[v] = 0;
    dfs(v, -1);
    for (auto &j : Tree) if (d[j] > d[v]) v = j;
    longest = max(longest, d[v]);

    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;
// }

Compilation message (stderr)

dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:67:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |     for (int i = 0; i < center.size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~

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