private void solveTrie(Node node) {
boolean isEvenNode = (node.depth % 2 == 0);
if (node.children.isEmpty()) {
if (node.depth >= 4) // only count 4+ length strings as goals
{
node.compGoal = !isEvenNode;
}
if (isEvenNode) {
node.depthOfUserGoal = node.depth;
} else {
node.depthOfCompGoal = node.depth;
}
return;
}
// node.compGoal = isEvenNode; // non-leaf initialization (done in constructor instead)
for (Node n : node.children.values()) {
solveTrie(n);
if (isEvenNode) { // it is the user's turn
if (!n.compGoal) {
// if there is a user goal to be chosen, this node is a user goal as well
// if no user goals can be chosen, this node is a computer goal
node.compGoal = false;
node.depthOfUserGoal =
(node.depthOfUserGoal > n.depthOfUserGoal) ? node.depthOfUserGoal : n.depthOfUserGoal;
node.userGoals.add(n);
} else {
node.compGoals.add(n);
// if the user cannot choose a user goal, he chooses the (computer-winning) path(s) that
// forces the maximal game length
// node.maxLosingPaths holds these path(s) and is updated here
updateMaxLosingPaths(node, n, "compGoals");
}
} else { // it is the computer's turn
if (n.compGoal) {
// if there is a computer goal to be chosen, this node is a computer goal as well
// if no computer goals can be chosen, this node is a user goal
node.compGoal = true;
node.depthOfCompGoal =
(node.depthOfCompGoal > n.depthOfCompGoal) ? node.depthOfCompGoal : n.depthOfCompGoal;
node.compGoals.add(n);
} else {
node.userGoals.add(n);
// if the computer cannot choose a computer goal, he chooses the (user-winning) path(s)
// that forces the maximal game length
// node.maxLosingPaths holds these path(s) and is updated here
updateMaxLosingPaths(node, n, "userGoals");
}
}
}
}
private void updateDepthOfGoal(Node node, Node n, String type) {
if (type.equals("compGoals")) {
node.depthOfCompGoal = n.depthOfCompGoal;
} else {
node.depthOfUserGoal = n.depthOfUserGoal;
}
}