Priority queue : Queue « Collections Data Structure « Java
Priority queue
public class PriorityQ {
// array in sorted order, from max at 0 to min at size-1
private int maxSize;
private long[] queArray;
private int nItems;
public PriorityQ(int s) {
maxSize = s;
queArray = new long[maxSize];
nItems = 0;
}
public void insert(long item) {
int i;
if (nItems == 0)
queArray[nItems++] = item; // insert at 0
else
{
for (i = nItems - 1; i >= 0; i--) // start at end,
{
if (item > queArray[i]) // if new item larger,
queArray[i + 1] = queArray[i]; // shift upward
else
// if smaller,
break; // done shifting
}
queArray[i + 1] = item; // insert it
nItems++;
} // end else (nItems > 0)
}
public long remove(){
return queArray[--nItems];
}
public long peekMin(){
return queArray[nItems - 1];
}
public boolean isEmpty(){
return (nItems == 0);
}
public boolean isFull(){
return (nItems == maxSize);
}
public static void main(String[] args) {
PriorityQ thePQ = new PriorityQ(5);
thePQ.insert(30);
thePQ.insert(50);
thePQ.insert(10);
thePQ.insert(40);
thePQ.insert(20);
while (!thePQ.isEmpty()) {
long item = thePQ.remove();
System.out.print(item + " "); // 10, 20, 30, 40, 50
}
System.out.println("");
}
}
