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#include <iostream>
#include <fstream>
#include <map>
#include <vector>
#define INF 9999999
using namespace std;
typedef pair<int, int> pii;
typedef tuple<int, int, int> tii;
class Graph
{
public:
explicit Graph(size_t size, size_t k)
: sizes_ { size }
, k_ { k }
{
for (size_t i = 0; i < size; ++i)
add_node(i);
}
Graph*
add_node(int x)
{
auto it = nodes_.find(x);
if (it != nodes_.end()) {
nodes_[x] = vector<pii>();
}
return this;
}
Graph*
add_edge(int x, int y, int w)
{
nodes_[x].push_back({y, w});
edges_.push_back({x, y, w});
return this;
}
void
bellmanford(int s, int r, ostream& out)
{
vector<int> dist(sizes_, INF);
dist[s] = 0;
for (size_t i = 0; i < min(k_, sizes_); ++i) {
for (const auto& e : edges_) {
auto u = get<0>(e);
auto v = get<1>(e);
auto w = get<2>(e);
if (dist[u] != INF && dist[v] > dist[u] + w) {
dist[v] = dist[u] + w;
}
}
}
if (dist[r] == INF) {
out << "inf." << endl;
} else {
out << dist[r] << endl;
}
}
private:
map<int, vector<pii>> nodes_;
vector<tii> edges_;
size_t sizes_;
size_t k_;
};
int
main(int argc, char** argv)
{
int nt = (argc > 1) ? stoi(argv[1]) : 100;
int n, m, k, s, r;
string ch;
int n1, n2, w;
ifstream fin("input.txt");
ofstream fout("output.txt");
for (int i = 0; i < nt; ++i) {
fin >> n >> m >> k;
Graph* g = new Graph(n, k);
for (int j = 0; j < m; ++j) {
fin >> ch;
n1 = stoi(ch.substr(1, ch.length()));
fin >> n2 >> ch;
w = stoi(ch.substr(0, ch.length()-1));
g->add_edge(n1, n2, w);
}
fin >> s >> r;
g->bellmanford(s, r, fout);
delete g;
}
fout.close();
fin.close();
return 0;
}
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