| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1135939 | dadas08 | Dreaming (IOI13_dreaming) | C++20 | 0 ms | 0 KiB |
#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
// #define ordered_set tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update>
// #define ordered_multiset tree<int, null_type, less_equal<int>, rb_tree_tag,tree_order_statistics_node_update>
using namespace std;
void _main();
int main() {
cin.tie(0);
ios::sync_with_stdio(false);
_main();
return 0;
}
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using vi = std::vector<int>;
using vvi = std::vector<vi>;
using vl = std::vector<ll>;
using vii = std::vector<pair<int, int> >;
using vvl = std::vector<vl>;
using vll = std::vector<pair<ll , ll> >;
using vd = std::vector<double>;
using vvd = std::vector<vd>;
using vs = std::vector<std::string>;
using vvs = std::vector<vs>;
using vb = std::vector<bool>;
using vvb = std::vector<vb>;
using vc = std::vector<char>;
using vvc = std::vector<vc>;
using pii = std::pair<int, int>;
using pll = std::pair<ll, ll>;
using piil = std::pair<pair<int, int>, ll>;
using mii = std::map<int, int>;
using mll = std::map<ll, ll>;
using pql = std::priority_queue<ll>;
using pqi = std::priority_queue<int>;
using pqiil = std::priority_queue<pair<pair<int, int>, ll> >;
using pqii = std::priority_queue<pair<int, int> >;
#define pb push_back
#define ps push
#define eb emplace_back
#define is insert
#define er erase
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define sf(i) sizeof(i)
#define endl "\n"
#define all(v) (v).begin(), (v).end()
#define rep(i, L, R) for(ll i = L;i<=R;i++)
#define pcis precision
#define sz(a) ((ll) a.size())
template<typename T>
struct infinity {
static constexpr T max=std::numeric_limits<T>::max();
static constexpr T min=std::numeric_limits<T>::min();
static constexpr T value=std::numeric_limits<T>::max()/2;
static constexpr T mvalue=std::numeric_limits<T>::min()/2;
};
template<typename T>constexpr T INF=infinity<T>::value;
constexpr ll lINF=INF<ll>;
constexpr int iINF = INF<int>;
constexpr ld PI = 3.1415926535897932384626;
ll N, M, L;
bool vst[100001];
vll adj[100001];
ll down[100001];
ll sz[100001];
void DFS1(ll node, ll par) {
sz[node] = 1;
for (auto [i, w] : adj[node]) {
if (i==par) continue;
DFS1(i, node);
sz[node] += sz[i];
down[node] = max(down[node], w + down[i]);
}
return;
}
ll DFS2(ll node, ll par, ll up) {
ll MN = max(up, down[node]);
vst[node] = true;
ll mx1 = up;
ll mxat = -1;
ll mx2 = 0;
for (auto [i, w] : adj[node]) {
if (i==par) continue;
if (down[i]+w >= mx1) {
mx2 = mx1;
mxat = i;
mx1 = down[i] + w;
} else if (down[i] + w >= mx2) {
mx2 = down[i] + w;
}
}
for (auto [i, w] : adj[node]) {
if (i==par) continue;
if (mxat == i) {
MN = min(MN, DFS2(i, node, mx2 + w));
} else {
MN = min(MN, DFS2(i, node, mx1 + w));
}
}
return MN;
}
void _main() {
cin >>N >>M >>L;
for (ll i = 1; i<=M; i++) {
ll a, b, c;
cin >>a >> b >> c;
adj[a].pb({b, c});
adj[b].pb({a, c});
}
vl lst;
for (ll i = 1; i<=N; i++) {
if (!vst[i]) {
DFS1(i, -1);
lst.pb(DFS2(i, -1, 0));
}
}
sort(all(lst));
reverse(all(lst));
if (lst.size() == 1) {
cout << lst[0] << endl;
} else if (lst.size() == 2) {
cout << lst[0] + lst[1] + L << endl;
} else {
cout << max(lst[0] + lst[1] + L, lst[1] + lst[2] + 2*L) << endl;
}
}