diff options
Diffstat (limited to 'I_anno')
| -rw-r--r-- | I_anno/Programmazione_2/data_structures/graph_stl.cc | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/I_anno/Programmazione_2/data_structures/graph_stl.cc b/I_anno/Programmazione_2/data_structures/graph_stl.cc new file mode 100644 index 0000000..5381747 --- /dev/null +++ b/I_anno/Programmazione_2/data_structures/graph_stl.cc @@ -0,0 +1,221 @@ +#include<iostream> +#include<vector> +#include<algorithm> +#include<queue> +#include<stack> +#define INF 99999999 +#define W -1 +#define G 0 +#define B 1 + +using namespace std; + +template<class H> +class graph { +public: + graph(int len) : _len{len}, _nodes{0}, _edges{0} { + _k = new H*[len]; + _adj = new vector<int>[len]; + _colors = new int[len]; + _d = new int[len]; + _f = new int[len]; + _p = new int[len]; + + for(int i = 0; i < len; ++i) { + _k[i] = nullptr; + } + } + ~graph() { + delete[] _k; + delete[] _adj; + } + + graph<H>* add_node(H x) { + if(_index(x) > -1) return this; + if(_nodes == _len) return this; + _k[_nodes++] = new H(x); + + return this; + } + graph<H>* add_edge(H u, H v) { + int i = _index(u); + int j = _index(v); + if(i < 0 || j < 0) return this; + + if(find(_adj[i].begin(), _adj[i].end(), j) == _adj[i].end()) { + _adj[i].push_back(j); + } + return this; + } + void print() { + for(int i = 0; i < _nodes; ++i) { + cout << "(" << *_k[i] << ", " << i << "): "; + for(auto const& j : _adj[i]) { + cout << "(" << *_k[j] << ", " << j << ") "; + } + cout << endl; + } + } + void dfsvisit(int u, bool visited[]) { + visited[u] = true; + cout << "(" << *_k[u] << ", " << u << ") "; + for(auto const& i : _adj[u]) { + if(!visited[i]) + dfsvisit(i, visited); + } + } + int dfsvisit(int u) { + int cycle = 0; + _colors[u] = G; + _d[u] = _time++; + + for(auto const& j : _adj[u]) { + if(_colors[j] == W) + cycle |= dfsvisit(j); + } + + _colors[u] = B; + _stack.push(u); + _f[u] = _time++; + return cycle; + } + int dfs() { + int cycle = 0; + for(int i = 0; i < _nodes; ++i) { + _colors[i] = W; + } + _time = 0; + for(int i = 0; i < _nodes; ++i) { + if(_colors[i] == W) + cycle |= dfsvisit(i); + else if(_colors[i] == G) + cycle = 1; + } + for(int i = 0; i < _nodes; ++i) { + cout << "(" << *_k[i] << ", " << i << "): [" << _d[i] << "," << _f[i] << "]" << endl; + } + return cycle; + } + + void top_sort() { + int cycle = dfs(); + if(cycle) { + cout << "cyclic graph!" << endl; + return; + } + int* s = new int[_nodes]; + for(int i = 0; i < _nodes; ++i) s[i] = i; + _sort(s, _nodes, _f); + for(int i = 0; i < _nodes; ++i) { + cout << "(" << s[i] << ", " << _f[s[i]] << ") "; + } + + } + + void bfs(H v) { + int s = _index(v); + if(s < 0) return; + + for(int i = 0; i < _nodes; ++i) { + _colors[i] = W; + _d[i] = INF; + _p[i] = -1; + } + _colors[s] = G; + _d[s] = 0; + queue<int> q; + q.push(s); + while(!q.empty()) { + int u = q.front(); + q.pop(); + for(auto const& j : _adj[u]) { + if(_colors[j] == W) { + _colors[j] = G; + _d[j] = _d[u]+1; + _p[j] = u; + q.push(j); + } + } + _colors[u] = B; + } + for(int i = 0; i < _nodes; ++i) { + cout << "(" << *_k[i] << ", " << i << "): [" << _d[i] << "]" << endl; + } + } + void ssc() { + dfs(); + cout << endl << endl; + auto gr = _transpose(); + bool* visited = new bool[_nodes]; + for(int i = 0; i < _nodes; ++i) + visited[i] = false; + + while(!_stack.empty()) { + int v = _stack.top(); + _stack.pop(); + if(!visited[v]) { + gr->dfsvisit(v, visited); + cout << endl; + } + } + delete[] visited; + } +private: + graph<H>* _transpose() { + graph<H>* g = new graph<H>{_len}; + for(int i = 0; i < _nodes; ++i) { + g->add_node(*_k[i]); + } + + for(int i = 0; i < _nodes; ++i) { + for(auto const& j : _adj[i]) { + g->add_edge(j, i); + } + } + + return g; + } + void _sort(int* d, int n, int* s) { + for(int i = -1; i < n; ++i) { + int j = i-1; + while(j > -1 && s[d[j+1]]>s[d[j]]) { + swap(d[s[j+1]], d[s[j]]); + --j; + } + } + } + int _index(H x) { + for(int i = 0; i < _nodes; ++i) + if(*_k[i] == x) return i; + + return -1; + } + stack<int> _stack; + H** _k; + vector<int>* _adj; + int _len, _nodes, _edges; + int* _colors; + int _time; + int* _d; + int* _f; + int* _p; +}; + +int main() { + graph<int>* g = new graph<int>{5}; + for(auto const& i : {0, 1, 2, 3, 4}) + g->add_node(i); + g->add_edge(1, 0); + g->add_edge(2, 1); + g->add_edge(0, 2); + g->add_edge(0, 3); + g->add_edge(3, 4); + //g->print(); + cout << endl; + //g->top_sort(); + g->ssc(); + cout << endl; + //g->bfs(0); + delete g; + return 0; +} |