SOURCE

var group= [1,9,3,5,0,4,2,8];


function mergeSort(list) {
    var length = list.length;
    if(length==1){ //结束条件
        return list;
        }
    var mid = Math.floor(length/2);
    var left = list.slice(0,mid);
    var right = list.slice(mid,length);
    return merge(mergeSort(left),mergeSort(right));//递归
};

function merge(left,right) {
    var result = [];
    var nl = 0;
    var nr =0;
    while(nl<left.length && nr<right.length){
        if(left[nl]<right[nr]){//按从小到大的顺序排列新的组合数组
            result.push(left[nl++]);//扔进去之后迭代
        }else{
            result.push(right[nr++]);
        }

    }
    while(nl<left.length){//剩下的一股脑儿扔进去。
        result.push(left[nl++]);

    }
    while(nr<right.length){
        result.push(right[nr++]);

    }
    return result;
}



  console.log(mergeSort(group));