let arr=[5,7,5,8,1,2,9,10,51];
let len=arr.length;
function a(arr){
    if(arr==null||arr.length<2) {return null;}

    for(let i=0;i<len;i++){
        heapinsert(arr,i);
    }

    let size=arr.length;
    swap(arr,0,--size);

    while(size>0){
        heap(arr,0,size);
        swap(arr,0,--size);        
    }
    return arr;
}

function heapinsert(arr,i){
    while(arr[i]>arr[Math.floor((i-1)/2)]){
        swap(arr,i,Math.floor((i-1)/2));
        i=Math.floor((i-1)/2);
    }
}

function heap(arr,index,size){
    let left=index*2 + 1;
    while(left<size){
        let lag=left+1<size && arr[left]<arr[left+1]?left+1:left;
        lag=arr[index]<arr[lag]?lag:index;
        if(lag===index){
            break;
        }
        swap(arr,lag,index)
        index=lag;
        left=index*2+1;
    }
}

function swap(arr,i,j){
    let tmp=arr[i];
    arr[i]=arr[j];
    arr[j]=tmp;
}

let b=a(arr);
console.log(b);