function DFS(node, parent) { // node = current node, parent = previous node

tracer._visit(node, parent)._wait();

D[node] = true; // label current node as discovered

for (var i = 0; i < G[node].length; i++) {

if (G[node][i]) { // if the edge from current node to the i-th node exists

if (!D[i]) { // if the i-th node is not labeled as discovered

DFS(i, node); // recursively call DFS

}

}

}

D[node] = false; // label current node as undiscovered

tracer._leave(node, parent)._wait();

}

var D; // D[i] indicates whether the i-th node is discovered or not

for (var i = 0; i < G.length; i++) { // start from every node

D = [];

for (var j = 0; j < G.length; j++) D.push(false);

logger._print('start from ' + i);

DFS(i);

tracer._clear();

}