Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 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 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 | 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 1245x 1245x 1245x 1245x 1245x 1245x 1245x 1245x 26x 26x 52411x 52411x 26x 26x 5766x 5766x 5766x 5766x 5766x 5766x 5766x 5766x 5766x 26x 26x 15144x 15144x 26x 26x 8778x 8778x 8778x 8778x 8778x 8778x 8778x 19390x 19390x 19390x 19390x 19390x 19390x 17249x 18291x 17249x 17249x 17249x 8778x 8778x 8778x 8778x 26x 26x 5767x 5767x 5767x 5767x 5767x 5767x 19852x 19852x 19852x 19256x 19256x 19298x 19256x 19256x 5767x 5767x 5767x 5767x 26x 26x 4225x 4225x 4225x 4225x 4225x 4225x 2717x 2717x 2716x 2716x 2717x 4225x 26x 26x 3602x 3602x 3602x 3602x 3597x 3597x 3597x 3597x 3602x 26x | 'use strict';
const {
Array,
Symbol,
} = primordials;
const kCompare = Symbol('compare');
const kHeap = Symbol('heap');
const kSetPosition = Symbol('setPosition');
const kSize = Symbol('size');
// The PriorityQueue is a basic implementation of a binary heap that accepts
// a custom sorting function via its constructor. This function is passed
// the two nodes to compare, similar to the native Array#sort. Crucially
// this enables priority queues that are based on a comparison of more than
// just a single criteria.
module.exports = class PriorityQueue {
constructor(comparator, setPosition) {
if (comparator !== undefined)
this[kCompare] = comparator;
if (setPosition !== undefined)
this[kSetPosition] = setPosition;
this[kHeap] = new Array(64);
this[kSize] = 0;
}
[kCompare](a, b) {
return a - b;
}
insert(value) {
const heap = this[kHeap];
const pos = ++this[kSize];
heap[pos] = value;
if (heap.length === pos)
heap.length *= 2;
this.percolateUp(pos);
}
peek() {
return this[kHeap][1];
}
percolateDown(pos) {
const compare = this[kCompare];
const setPosition = this[kSetPosition];
const heap = this[kHeap];
const size = this[kSize];
const item = heap[pos];
while (pos * 2 <= size) {
let childIndex = pos * 2 + 1;
if (childIndex > size || compare(heap[pos * 2], heap[childIndex]) < 0)
childIndex = pos * 2;
const child = heap[childIndex];
if (compare(item, child) <= 0)
break;
if (setPosition !== undefined)
setPosition(child, pos);
heap[pos] = child;
pos = childIndex;
}
heap[pos] = item;
if (setPosition !== undefined)
setPosition(item, pos);
}
percolateUp(pos) {
const heap = this[kHeap];
const compare = this[kCompare];
const setPosition = this[kSetPosition];
const item = heap[pos];
while (pos > 1) {
const parent = heap[pos / 2 | 0];
if (compare(parent, item) <= 0)
break;
heap[pos] = parent;
if (setPosition !== undefined)
setPosition(parent, pos);
pos = pos / 2 | 0;
}
heap[pos] = item;
if (setPosition !== undefined)
setPosition(item, pos);
}
removeAt(pos) {
const heap = this[kHeap];
const size = --this[kSize];
heap[pos] = heap[size + 1];
heap[size + 1] = undefined;
if (size > 0 && pos <= size) {
if (pos > 1 && this[kCompare](heap[pos / 2 | 0], heap[pos]) > 0)
this.percolateUp(pos);
else
this.percolateDown(pos);
}
}
shift() {
const heap = this[kHeap];
const value = heap[1];
if (value === undefined)
return;
this.removeAt(1);
return value;
}
};
|