js 歸併算法

將數組遞歸分裂成單個元素 然後合併數組

let data3 = [14, 54, 73, 38, 39, 67, 75, 80, 50, 40, 96, 27, 105, 109, 77, 31]
function breakArr (data,start,end){
      if (start < end) {

 let mid = Math.floor((start + end)/2)      
          breakArr(data,start,mid)
          breakArr(data,mid+1,end)
          combineArr(data,start,mid,end)
                }

 }
 function combineArr(data,start,mid,end){

     let i = start,j=mid+1;
     let m = mid,  n=end;

     let k = 0;
     let  temp = []
     while(i<=m && j<=n){
          if (data[i]<=data[j]) 
              temp[k++] = data[i++]

          else  
              temp[k++] = data[j++]
        }
    while(i<=m)
         temp[k++] = data[i++];

    while(j<=n)
         temp[k++] = data[j++];

    for ( i = 0; i < k; i++) {
        data[start + i] = temp[i]
    }

    console.log(temp)
 }


 breakArr(data3,0,15)