-
Notifications
You must be signed in to change notification settings - Fork 0
/
PriorityQueue.java
88 lines (77 loc) · 1.77 KB
/
PriorityQueue.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
package datastructure.queue.priorityqueue;
/**
* @Author john
* @Description 通用优先队列
* @Date 2022/10/1 下午5:09
*/
public final class PriorityQueue<T> {
private int size;
private final int capacity;
private final transient Object[] q;
private final Less<T> cmp;
public PriorityQueue(int n, Less<T> lessT) {
size = 0;
capacity = n;
q = new Object[n];
cmp = lessT;
}
public boolean isEmpty() {
return size == 0;
}
private boolean isFull() {
return size == capacity;
}
public void push(T t) {
q[size] = t;
size++;
up(size - 1);
}
@SuppressWarnings("unchecked")
public T pop() {
T top = (T)q[0];
size--;
q[0] = q[size];
down(0);
return top;
}
private void swap(int i, int j) {
Object t = q[i];
q[i] = q[j];
q[j] = t;
}
@SuppressWarnings("unchecked")
public T top() {
return (T)q[0];
}
private void up(int p) {
while (p > 0) {
int r = (p - 1) / 2;
if (less(r, p)) {
return;
}
swap(r, p);
p = r;
}
}
private void down(int p) {
while (p < size) {
int small = p, l = 2 * p + 1;
if (l < size && less(l, small)) {
small = l;
}
int r = l + 1;
if (r < size && less(r, small)) {
small = r;
}
if (small == p) {
return;
}
swap(small, p);
p = small;
}
}
@SuppressWarnings("unchecked")
private boolean less(int i, int j) {
return cmp.less((T)q[i], (T)q[j]);
}
}