| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 288287 | BeanZ | Dreaming (IOI13_dreaming) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
//#include "dreaming.h"
using namespace std;
#define ll long long
#define endl '\n'
const int N = 1e5 + 5;
ll dp[N], res, vis[N], lg, cur;
vector<pair<ll, ll>> node[N];
void dfsFirst(ll u){
vis[u] = 1;
for (auto j : node[u]){
if (vis[j.first]) continue;
dfsFirst(j.first);
dp[u] = max(dp[u], dp[j.first] + j.second);
}
}
void reroot(ll u, ll v){
dp[u] = 0;
for (auto j : node[u]){
if (j.first == v) continue;
dp[u] = max(dp[u], dp[j.first] + j.second);
}
dp[v] = 0;
for (auto j : node[v]){
dp[v] = max(dp[v], dp[j.first] + j.second);
}
res = min(res, dp[v]);
}
void dfs(ll u, ll p){
for (auto j : node[u]){
if (j.first == p) continue;
reroot(u, j.first);
dfs(j.first, u);
reroot(j.first, u);
}
}
void FindFirstNode(ll u, ll p, ll dist){
if (dist > lg){
lg = dist;
cur = u;
}
for (auto j : node[u]){
if (j.first == p) continue;
FindFirstNode(j.first, u, dist + j.second);
}
}
void FindDia(ll u, ll p, ll dist){
if (dist > lg){
lg = dist;
}
for (auto j : node[u]){
if (j.first == p) continue;
FindDia(j.first, u, dist + j.second);
}
}
int travelTime(int N, int M, int L, int A[],int B[],int T[]){
for (int i = 1; i <= M; i++){
node[A[i - 1] + 1].push_back({B[i - 1] + 1, T[i - 1]});
node[B[i - 1] + 1].push_back({A[i - 1] + 1, T[i - 1]});
}
priority_queue<ll> pq;
ll ans = 0;
for (int i = 1; i <= N; i++){
if (!vis[i]){
dfsFirst(i);
res = dp[i];
dfs(i, i);
lg = -1;
FindFirstNode(i, i, 0);
lg = -1;
FindDia(cur, cur, 0);
ans = max(ans, lg);
pq.push(res);
}
}
ll root = pq.top();
pq.pop();
ll mx = -1e18;
while (pq.size()){
ans = max(ans, pq.top() + 2 * L + mx);
ans = max(ans, pq.top() + L + root);
mx = max(mx, pq.top());
pq.pop();
}
return ans;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
if (fopen("VietCT.INP", "r")){
freopen("VietCT.INP", "r", stdin);
freopen("VietCT.OUT", "w", stdout);
}
int n, m, l;
cin >> n >> m >> l;
vector<int> a, b, t;
for (int i = 1; i <= m; i++){
int u, v, c;
cin >> u >> v >> c;
a.push_back(u + 1);
b.push_back(v + 1);
t.push_back(c);
}
cout << travelTime(n, m, l, a, b, t);
}
/*
6 2 1000
0 1 10
2 3 10
*/