//#include"dreaming.h"
#include <bits/stdc++.h>
using namespace std;
struct edge
{
long long u, w;
};
struct tpos
{
long long nodo, dist, padre;
};
vector<vector<edge>> adj;
pair<long long, long long> bfs (long long nodo, long long N)
{
// cout << "nodo: " << nodo << '\n';
pair<long long, long long> ret;
ret.second = -1;
queue<tpos> q;
q.push({nodo, 0, -1});
tpos temp_tpos;
vector<bool> visi(N);
while (!q.empty())
{
temp_tpos = q.front(); q.pop();
visi[temp_tpos.nodo] = 1;
//cout << " " << temp_tpos.nodo << " " << temp_tpos.dist << "\n";
for (edge e: adj[temp_tpos.nodo])
{
// cout << temp_tpos.nodo << " vecinos: " << e.u << '\n';
if (visi[e.u]) continue;
q.push({e.u, temp_tpos.dist+e.w, temp_tpos.nodo});
}
if (temp_tpos.dist > ret.second)
{
ret.second = temp_tpos.dist;
ret.first = temp_tpos.nodo;
}
}
//cout << '\n';
return ret;
}
long long Diametro (long long N)
{
long long ve = bfs(0, N).first;
return bfs(ve, N).second;
}
struct dsu
{
struct componente
{
long long representante;
long long inicio_diametro, fin_diametro;
long long punto_medio, distancia_punto_medio;
vector <long long> miembros;
long long diametro;
map<long long, long long> distancia_diametro;
pair<long long, long long> other_bfs (long long nodo, bool pasada)
{
pair<long long, long long> ret;
ret.second = -1;
queue<tpos> q;
q.push({nodo, 0, -1});
tpos temp_tpos;
while (!q.empty())
{
temp_tpos = q.front(); q.pop();
if (pasada)
distancia_diametro[temp_tpos.nodo] = temp_tpos.dist;
for (edge e: adj[temp_tpos.nodo])
{
if (e.u == temp_tpos.padre) continue;
q.push({e.u, temp_tpos.dist+e.w, temp_tpos.nodo});
}
if (temp_tpos.dist > ret.second)
{
ret.second = temp_tpos.dist;
ret.first = temp_tpos.nodo;
}
}
return ret;
}
void get_punto_medio ()
{
long long mini = 1<<30;
for (long long i = 0; i < miembros.size(); i++)
{
long long temp_dist = distancia_diametro[miembros[i]];
// cout << miembros[i] << " -> " << temp_dist << '\n';
long long temp_longlong = max(temp_dist, diametro - temp_dist);
if (mini > temp_longlong)
{
mini = temp_longlong;
punto_medio = miembros[i];
}
distancia_punto_medio = mini;
}
}
void get_diametro()
{
if (miembros.size() > 1)
{
long long resp = other_bfs(representante, 0).first;
inicio_diametro = resp;
pair<long long, long long> temp_pair = other_bfs(resp, 1);
fin_diametro = temp_pair.first;
diametro = temp_pair.second;
}
else
{
diametro = 0;
distancia_diametro[miembros[0]] = 0;
inicio_diametro = miembros[0];
fin_diametro = miembros[0];
}
// cout << representante << ": \n";
get_punto_medio();
}
};
long long N;
vector<long long>parent;
vector<componente> arboles;
vector<vector<long long>> miembros_de_componente;
dsu(long long n)
{
parent.resize(n);
N = n;
miembros_de_componente.resize(n);
for (long long i = 0; i < N; i++)
parent[i] = i;
}
void une (long long a, long long b)
{
parent[busca(a)] = busca(b);
}
long long busca (long long a)
{
if (parent[a] == a) return a;
return (parent[a] = busca(parent[a]));
}
void crea_componentes()
{
for (long long i = 0; i < N; i++)
miembros_de_componente[busca(i)].push_back(i);
for (long long i = 0; i < N; i++)
{
if (miembros_de_componente[i].empty()) continue;
componente comp_temp;
comp_temp.representante = i;
comp_temp.miembros = miembros_de_componente[i];
arboles.push_back(comp_temp);
arboles.back().get_diametro();
//cout << '\n';
}
}
};
int travelTime(int N, int M, int L, int A[], int B[], int T[])
{
// cout << '\n';
adj.resize(N);
edge temp_edge;
dsu bosque(N);
for (long long i = 0; i < M; i++)
{
temp_edge.u = B[i];
temp_edge.w = T[i];
adj[A[i]].push_back(temp_edge);
temp_edge.u = A[i];
adj[B[i]].push_back(temp_edge);
bosque.une(A[i], B[i]);
}
bosque.crea_componentes();
long long temp_mid_pnt;
long long cnt = 1;
vector<long long> mid_points;
for (dsu::componente c: bosque.arboles)
mid_points.push_back(c.punto_medio);
// cout << '\n';
for (long long i = 1; i < mid_points.size(); i++)
{
edge temp_edge;
temp_edge.u = mid_points[i-1];
temp_edge.w = L;
adj[mid_points[i]].push_back(temp_edge);
temp_edge.u = mid_points[i];
adj[mid_points[i-1]].push_back(temp_edge);
}
/* for (long long i = 0; i < N; i++)
{
cout << i << ": ";
for (edge e: adj[i])
cout << e.u << " ";
cout << '\n';
}
*/
return Diametro(N);
}
int main()
{
long long N, M, L;
cin >> N >> M >> L;
int A[M], B[M], T[M];
for (long long i = 0; i < M; i++)
cin >> A[i] >> B[i] >> T[i];
cout << travelTime(N, M, L, A, B, T) << endl;
return 0;
}
Compilation message
dreaming.cpp: In member function 'void dsu::componente::get_punto_medio()':
dreaming.cpp:87:37: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
87 | for (long long i = 0; i < miembros.size(); i++)
| ~~^~~~~~~~~~~~~~~~~
dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:187:29: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
187 | for (long long i = 1; i < mid_points.size(); i++)
| ~~^~~~~~~~~~~~~~~~~~~
dreaming.cpp:179:15: warning: unused variable 'temp_mid_pnt' [-Wunused-variable]
179 | long long temp_mid_pnt;
| ^~~~~~~~~~~~
dreaming.cpp:180:15: warning: unused variable 'cnt' [-Wunused-variable]
180 | long long cnt = 1;
| ^~~
/usr/bin/ld: /tmp/ccOwdnpW.o: in function `main':
dreaming.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/ccvz1OuV.o:grader.c:(.text.startup+0x0): first defined here
/usr/bin/ld: /tmp/ccvz1OuV.o: in function `main':
grader.c:(.text.startup+0xd1): undefined reference to `travelTime'
collect2: error: ld returned 1 exit status
