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#include<iostream>
#include<vector>
#include<queue>
#define W -1
#define G 0
#define B 1
using namespace std;
template<class H>
class node {
public:
explicit node(H key, node<H>* next) : _key{key}, _next(next) {}
const H& key() const { return _key; }
H& key() { return _key; }
const node<H>*& next() const { return _next; }
node<H>*& next() { return _next; }
private:
H _key;
node<H>* _next;
};
template<class H>
class list {
public:
list() : _head{nullptr} {}
~list() {
while(_head) {
auto tmp = _head;
_head = _head->next();
delete tmp;
}
}
list<H>* push(H val) {
auto iter = _head;
while(iter && iter->next())
iter = iter->next();
if(!iter)
_head = new node<H>{val, nullptr};
else
iter->next() = new node<H>{val, nullptr};
return this;
}
void print() {
auto iter = _head;
while(iter) {
cout << iter->key() << ' ';
iter = iter->next();
}
}
vector<H> as_vector() {
vector<H> v;
auto iter = _head;
while(iter) {
v.push_back(iter->key());
iter = iter->next();
}
return v;
}
node<H>* search(H val) {
auto iter = _head;
while(iter && iter->key() != val) {
iter = iter->next();
}
return iter;
}
private:
node<H>* _head;
};
template<class H>
class graph {
public:
private:
int _len, _nodes, _edges;
int* _parents;
int* _distances;
H** _k; // it works like a dictionary, it saves the keys
list<int>** _adj;
int _index(H val) {
for(int i = 0; i < _nodes; ++i)
if(*_k[i] == val) return i;
return -1;
}
public:
graph(int len) : _len{len}, _nodes{0}, _edges{0} {
_k = new H*[len];
_adj = new list<int>*[_len];
_parents = new int[_len];
_distances = new int[_len];
for(int i = 0; i < _len; ++i) {
_k[i] = nullptr;
_adj[i] = new list<int>{};
}
}
graph<H>* add_node(H k) {
if(_nodes == _len) return this;
if(_index(k) >= 0) return this; // node is already there
_k[_nodes++] = new H(k);
return this;
}
void bfs(int s) {
int colors[_len];
queue<int> q;
for(int i = 0; i < _nodes; ++i) {
colors[i] = W;
_parents[i] = -1;
_distances[i] = 999999999;
}
q.push(s);
colors[s] = G;
_distances[s] = 0;
while(!q.empty()) {
int x = q.front();
q.pop();
for(auto const& j : _adj[x]->as_vector()) {
if(colors[j] == W) {
colors[j] = G;
q.push(j);
_parents[j] = x;
_distances[j] = _distances[x] + 1;
}
}
colors[x] = B;
}
for(int i = 0; i < _nodes; ++i) {
cout << "[" << i << "]->";
if(_distances[i]==999999999) cout << "inf." << endl;
else cout << _distances[i] << endl;
}
}
void bfs(H x) {
int s = _index(x);
if(s != -1)
bfs(s);
}
graph<H>* add_edge(H x, H y) {
int i = _index(x);
int j = _index(y);
if(i < 0 || j < 0) return this;
if(!_adj[i]->search(j)) {
_adj[i]->push(j);
_edges++;
}
return this;
}
void print() {
for(int i = 0; i < _nodes; ++i) {
cout << "(" << i << ", " << *_k[i] << "): ";
for(auto const& j : _adj[i]->as_vector())
cout << "(" << j << ", " << *_k[j] << "), ";
cout << '\n';
}
}
};
int main() {
graph<string>* g = new graph<string>(5);
g->add_node("hello")->add_node("greg")->add_node("yes");
g->add_node("nop")->add_node("ok");
g->add_edge("hello", "ok");
g->add_edge("ok", "yes")->add_edge("yes", "ok")->add_edge("yes", "yes");
g->add_edge("yes", "nop");
g->print();
g->bfs("hello");
delete g;
return 0;
}
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