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@knowankit
Created February 6, 2022 06:14
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Implementation of max and min heap in Javascript
/* Heaps */
// left child: i * 2
// right child: i * 2 + 1
// parent: i / 2
let MinHeap = function() {
let heap = [null];
this.insert = function(num) {
heap.push(num);
if (heap.length > 2) {
let idx = heap.length - 1;
while (heap[idx] < heap[Math.floor(idx/2)]) {
if (idx >= 1) {
[heap[Math.floor(idx/2)], heap[idx]] = [heap[idx], heap[Math.floor(idx/2)]];
if (Math.floor(idx/2) > 1) {
idx = Math.floor(idx/2);
} else {
break;
};
};
};
};
};
this.remove = function() {
let smallest = heap[1];
if (heap.length > 2) {
heap[1] = heap[heap.length - 1];
heap.splice(heap.length - 1);
if (heap.length == 3) {
if (heap[1] > heap[2]) {
[heap[1], heap[2]] = [heap[2], heap[1]];
};
return smallest;
};
let i = 1;
let left = 2 * i;
let right = 2 * i + 1;
while (heap[i] >= heap[left] || heap[i] >= heap[right]) {
if (heap[left] < heap[right]) {
[heap[i], heap[left]] = [heap[left], heap[i]];
i = 2 * i
} else {
[heap[i], heap[right]] = [heap[right], heap[i]];
i = 2 * i + 1;
};
left = 2 * i;
right = 2 * i + 1;
if (heap[left] == undefined || heap[right] == undefined) {
break;
};
};
} else if (heap.length == 2) {
heap.splice(1, 1);
} else {
return null;
};
return smallest;
};
this.sort = function() {
let result = new Array();
while (heap.length > 1) {
result.push(this.remove());
};
return result;
};
};
let MaxHeap = function() {
let heap = [null];
this.print = () => heap;
this.insert = function(num) {
heap.push(num);
if (heap.length > 2) {
let idx = heap.length - 1;
while (heap[idx] > heap[Math.floor(idx/2)]) {
if (idx >= 1) {
[heap[Math.floor(idx/2)], heap[idx]] = [heap[idx], heap[Math.floor(idx/2)]];
if (Math.floor(idx/2) > 1) {
idx = Math.floor(idx/2);
} else {
break;
};
};
};
};
};
this.remove = function() {
let smallest = heap[1];
if (heap.length > 2) {
heap[1] = heap[heap.length - 1];
heap.splice(heap.length - 1);
if (heap.length == 3) {
if (heap[1] < heap[2]) {
[heap[1], heap[2]] = [heap[2], heap[1]];
};
return smallest;
};
let i = 1;
let left = 2 * i;
let right = 2 * i + 1;
while (heap[i] <= heap[left] || heap[i] <= heap[right]) {
if (heap[left] > heap[right]) {
[heap[i], heap[left]] = [heap[left], heap[i]];
i = 2 * i
} else {
[heap[i], heap[right]] = [heap[right], heap[i]];
i = 2 * i + 1;
};
left = 2 * i;
right = 2 * i + 1;
if (heap[left] == undefined || heap[right] == undefined) {
break;
};
};
} else if (heap.length == 2) {
heap.splice(1, 1);
} else {
return null;
};
return smallest;
};
};
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