11const minHeapJSCode = `
2- class MinHeap {
3-
4- constructor () {
5- /* Initialing the array heap and adding a dummy element at index 0 */
6- this.heap = [null]
2+ function minHeap(A = []) {
3+ this.heapify(A);
4+ }
5+
6+ minHeap.prototype._shiftUp = function(i) {
7+ let parent_i = (i / 2) >>> 0;
8+ while (parent_i > 0) {
9+ if (this.h[i] < this.h[parent_i]) {
10+ [this.h[i], this.h[parent_i]] = [this.h[parent_i], this.h[i]];
11+ }
12+ parent_i = (parent_i / 2) >>> 0;
713 }
8-
9- peek() {
10- /* Accessing the min element at index 1 in the heap array */
11- return this.heap[1]
14+ };
15+
16+ minHeap.prototype._shiftDown = function(i) {
17+ while (i * 2 <= this.h.length - 1) {
18+ const mc = this._minChild(i);
19+ if (this.h[i] > this.h[mc]) {
20+ [this.h[i], this.h[mc]] = [this.h[mc], this.h[i]];
21+ }
22+ i = mc;
1223 }
13-
14- push (node) {
15-
16- /* Inserting the new node at the end of the heap array */
17- this.heap.push(node)
18-
19- /* Finding the correct position for the new node */
20-
21- if (this.heap.length > 1) {
22- let current = this.heap.length - 1
23-
24- /* Traversing up the parent node until the current node (current) is greater than the parent (current/2)*/
25- while (current > 1 && this.heap[Math.floor(current/2)] > this.heap[current]) {
26-
27- /* Swapping the two nodes by using the ES6 destructuring syntax*/
28- [this.heap[Math.floor(current/2)], this.heap[current]] = [this.heap[current], this.heap[Math.floor(current/2)]]
29- current = Math.floor(current/2)
30- }
31- }
32- }
33-
34- pop() {
35- /* Smallest element is at the index 1 in the heap array */
36- let smallest = this.heap[1]
37-
38- /* When there are more than two elements in the array, we put the right most element at the first position
39- and start comparing nodes with the child nodes
40- */
41- if (this.heap.length > 2) {
42- this.heap[1] = this.heap[this.heap.length-1]
43- this.heap.splice(this.heap.length - 1)
44-
45- if (this.heap.length === 3) {
46- if (this.heap[1] > this.heap[2]) {
47- [this.heap[1], this.heap[2]] = [this.heap[2], this.heap[1]]
48- }
49- return smallest
50- }
51-
52- let current = 1
53- let leftChildIndex = current * 2
54- let rightChildIndex = current * 2 + 1
55-
56- while (this.heap[leftChildIndex] &&
57- this.heap[rightChildIndex] &&
58- (this.heap[current] > this.heap[leftChildIndex] ||
59- this.heap[current] > this.heap[rightChildIndex])) {
60- if (this.heap[leftChildIndex] < this.heap[rightChildIndex]) {
61- [this.heap[current], this.heap[leftChildIndex]] = [this.heap[leftChildIndex], this.heap[current]]
62- current = leftChildIndex
63- } else {
64- [this.heap[current], this.heap[rightChildIndex]] = [this.heap[rightChildIndex], this.heap[current]]
65- current = rightChildIndex
66- }
67-
68- leftChildIndex = current * 2
69- rightChildIndex = current * 2 + 1
70- }
71- }
72-
73- /* If there are only two elements in the array, we directly splice out the first element */
74-
75- else if (this.heap.length === 2) {
76- this.heap.splice(1, 1)
77- } else {
78- return null
79- }
80-
81- return smallest
24+ };
25+
26+ minHeap.prototype._minChild = function(i) {
27+ if (i * 2 + 1 > this.h.length - 1) return i * 2;
28+ if (this.h[i * 2] < this.h[i * 2 + 1]) return i * 2;
29+ return i * 2 + 1;
30+ };
31+
32+ minHeap.prototype.pop = function() {
33+ if (this.h.length === 1) throw new Error('空了就别弹了吧？');
34+ const ans = this.h[1];
35+ this.h[1] = this.h[this.h.length - 1];
36+ this.h.pop();
37+ this._shiftDown(1);
38+ return ans;
39+ };
40+
41+ minHeap.prototype.push = function(a) {
42+ this.h.push(a);
43+ this._shiftUp(this.h.length - 1);
44+ console.log(this.h);
45+ };
46+
47+ minHeap.prototype.heapify = function(A) {
48+ this.h = [0].concat(A);
49+ i = 1;
50+ while (i < this.h.length) {
51+ this._shiftDown(i);
52+ i++;
8253 }
83- /**
84- * Your MinHeap object will be instantiated and called as such:
85- * var obj = new MinHeap()
86- * obj.push(1)
87- * obj .push(2)
88- * obj.peek() // will return 1
89- * obj .pop() // remove 1
90- * obj.peek() // will return 2
91- */
54+ };
55+
56+ // test:
57+ h = new minHeap([1, 2, 3]);
58+ h .push(4);
59+ h.push(5);
60+ h .pop();
61+ h.pop();
62+ console.log(h.h); // inspect internal value
9263}
9364` ;
9465
9566const minHeapPythonCode = `
9667class min_heap:
97- def __init__(self):
98- self.h = [0]
68+ def __init__(self, A=[] ):
69+ self.heapify(A)
9970
10071 def shift_up(self, i):
10172 while i // 2 > 0:
@@ -131,7 +102,7 @@ class min_heap:
131102 self.h.append(a)
132103 self.shift_up(len(self.h)-1)
133104
134- def build_heap (self, A):
105+ def heapify (self, A):
135106 self.h = [0] + A
136107 i = 1
137108 while (i < len(self.h)):
@@ -140,8 +111,7 @@ class min_heap:
140111
141112# 使用：
142113
143- h = min_heap()
144- h.build_heap([5, 6, 2, 3])
114+ h = min_heap([5, 6, 2, 3])
145115
146116h.heappush(1)
147117h.heappop() # 1
@@ -293,6 +263,5 @@ module.exports = {
293263 ] ,
294264 } ,
295265 ] ,
296- link :
297- "https://leetcode-solution.cn/solutionDetail?url=https%3A%2F%2Fapi.github.com%2Frepos%2Fazl397985856%2Fleetcode%2Fcontents%2Fthinkings%2Fheap.md&type=1" ,
266+ link : "https://leetcode-solution.cn/solutionDetail?url=https%3A%2F%2Fapi.github.com%2Frepos%2Fazl397985856%2Fleetcode%2Fcontents%2Fthinkings%2Fheap.md&type=1" ,
298267} ;
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