ヒープのJavaScript実装方法を詳しく解説

nLeftIndex = 2 * (nFatherIndex+1) - 1;
nRightIndex = 2* (nFatherIndex+1);

/******************************************************
* file : 堆
* author : "page"
* time : "2016/11/02"
*******************************************************/
function Heap()
{
 this.data = [];
}
 
Heap.prototype.print = function () {
 console.log("Heap: " + this.data);
}
 
Heap.prototype.build = function(data){
 // 初始化
 this.data = [];
 if (!data instanceof Array)
 return false;
 
 // 入堆
 for (var i = 0; i < data.length; ++i) {
 this.insert(data[i]);
 }
 
 return true;
}
 
Heap.prototype.insert = function( nValue ){
 if (!this.data instanceof Array) {
 this.data = [];
 }
 
 this.data.push(nValue);
 // 更新新节点
 var nIndex = this.data.length-1;
 var nFatherIndex = Math.floor((nIndex-1)/2);
 while (nFatherIndex > 0){
 if (this.data[nIndex] < this.data[nFatherIndex]) {
 var temp = this.data[nIndex];
 this.data[nIndex] = this.data[nFatherIndex];
 this.data[nFatherIndex] = temp;
 }
 
 nIndex = nFatherIndex;
 nFatherIndex = Math.floor((nIndex-1)/2);
 }
}
 
Heap.prototype.delete = function( ){
 if (!this.data instanceof Array) {
 return null;
 }
 
 var nIndex = 0;
 var nValue = this.data[nIndex];
 var nMaxIndex = this.data.length-1;
 // 更新新节点
 var nLeaf = this.data.pop();
 this.data[nIndex] = nLeaf;
 
 while (nIndex < nMaxIndex ){
 var nLeftIndex = 2 * (nIndex+1) - 1;
 var nRightIndex = 2 * (nIndex+1);
 
 // 找最小的一个子节点(nLeftIndex < nRightIndex)
 var nSelectIndex = nLeftIndex;
 if (nRightIndex < nMaxIndex) {
 nSelectIndex = (this.data[nLeftIndex] > this.data[nRightIndex]) ? nRightIndex : nLeftIndex;
 }
 
 if (nSelectIndex < nMaxIndex && this.data[nIndex] > this.data[nSelectIndex] ){
 var temp = this.data[nIndex];
 this.data[nIndex] = this.data[nSelectIndex];
 this.data[nSelectIndex] = temp;
 }
 
 nIndex = nSelectIndex;
 }
 
 return nValue;
}
// test
var heap = new Heap();
heap.build([1, 3, 5, 11, 4, 6, 7, 12, 15, 10, 9, 8]);
heap.print();
// insert
heap.insert(2);
heap.print();
// delete
heap.delete();
heap.print();