CantidateSolution GenerateRandomStart() {
// Hash set containing an entry for each bid
HashSet<Integer> Avail = new HashSet<Integer>();
Integer count = _bids.size();
for (Integer index = 0; index < count; index++) {
Avail.add(index);
}
// Generate Random Solution
Random gen = new Random();
// list of selected bids
LinkedList<Integer> bidlist = new LinkedList<Integer>();
// The total value of selected bids
Double value = 0.0;
// Here's the algorithym to select a random solution
// 1. Choose a bid at random from the avaialble set.
// 2. Put the chosen bid in the Bids list.
// 3. Go through all the bids remaining in the available set and remove any colliding bids.
// 4. Repeat from step 1 until no bids remain.
// The bid list now contains a valid solution chosen at random.
// Iterate as long as anything is left in the "available set"
while (Avail.size() > 0) {
// generate a random integer between 0 and the size of the Available set.
Integer newbid = gen.nextInt(Avail.size());
// Randomly choose an integer out of the Avail Set
newbid = (Integer) Avail.toArray()[newbid];
// Add the value of the chosen bid
value += _bids.get(newbid).value;
// Add the chosen bid to the bidList (a list of integers)
bidlist.add(newbid);
RemoveColidingBids(_bids.get(newbid), Avail);
}
CantidateSolution sol = new CantidateSolution();
// Collections.sort(bidlist);
sol.value = value;
sol.bids = bidlist;
return sol;
}
CantidateSolution GenerateGoodStart(long offset) {
// Hash set containing an entry for each bid
HashSet<Integer> Avail = new HashSet<Integer>();
Integer count = _bids.size();
LinkedList<Integer> SortedBids = new LinkedList<Integer>();
for (Integer index = 0; index < count; index++) {
Avail.add(index);
SortedBids.add(index);
}
if (offset < SortedBids.size()) {
for (int remove = 0; remove < offset; remove++) {
SortedBids.removeFirst();
}
}
// Sort the bids
Collections.sort(SortedBids, new RegionAvgCmp(_bids));
// list of selected bids
LinkedList<Integer> bidlist = new LinkedList<Integer>();
// The total value of selected bids
Double value = 0.0;
Random gen = new Random();
while (Avail.size() > 0) {
Integer newbid;
if (SortedBids.size() > 0) {
newbid = SortedBids.removeFirst();
} else {
// generate a random integer between 0 and the size of the Available set.
newbid = gen.nextInt(Avail.size());
// Randomly choose an integer out of the Avail Set
newbid = (Integer) Avail.toArray()[newbid];
}
// Add the value of the chosen bid
value += _bids.get(newbid).value;
// Add the chosen bid to the bidList (a list of integers)
bidlist.add(newbid);
RemoveColidingBids(_bids.get(newbid), Avail);
// clean out our SortedBidsList
Iterator<Integer> li = SortedBids.iterator();
while (li.hasNext()) {
Integer bidItem = li.next();
if (!Avail.contains(bidItem)) {
li.remove();
}
}
}
CantidateSolution sol = new CantidateSolution();
// Collections.sort(bidlist);
sol.value = value;
sol.bids = bidlist;
return sol;
}
