Merge pull request #32 from dcariotti/patch-1

DFS with stack

Graph/DFS_with_stack.cc

@@ -0,0 +1,53 @@
+#include <iostream>
+#include <list>
+#include <stack>
+
+
+#define WHITE 0
+#define GREY 1
+#define BLACK 2
+#define INF 99999
+
+using namespace std;
+
+int checked[999] = {WHITE};
+
+void dfs(const list<int> lista[], int start) {
+    stack<int> stack;
+
+    int checked[999] = {WHITE};
+   
+    stack.push(start);
+   
+    checked[start] = GREY;
+    while(!stack.empty()) {
+        int act = stack.top();
+        stack.pop();
+
+        if(checked[act] == GREY) {
+            cout << act << ' ';
+            for(auto it = lista[act].begin(); it != lista[act].end(); ++it) {
+                stack.push(*it);
+                if(checked[*it] != BLACK)
+                    checked[*it] = GREY;
+            }
+            checked[act] = BLACK; //nodo controllato
+        }
+    }
+}
+
+int main() {
+	int u, w;
+	int n;
+	cin >> n;
+	list<int> lista[INF];
+	for(int i = 0; i < n; ++i) {
+		cin >> u >> w;
+		lista[u].push_back(w);
+	}
+
+	dfs(lista, 0);
+	
+
+	return 0;
+}