技術標籤：演算法演算法

將陣列一分為二，直至只有一個元素

function mergeSort(arr){
    let len=arr.length;
    if(len<2){
        return arr;
    }
    var middle=Math.floor(len/2),
    left=arr.slice(0,middle),
    right=arr.slice(middle);
    return merge(mergeSort(left),mergeSort(right));
}
function merge(left,right){
    var result=[],
    len1=left.length,
    len2=right.length,
    i=0,
    j=0;

    while(i<len1&&j<len2){
        if(left[i]<=right[j]){
            result.push(left[i]);
            i++;
        }else{
            result.push(right[j]);
            j++
        }
    }

    while(i<len1){
        result.push(left[i]);
        i++;
    }
    while(j<len2){
        result.push(right[j]);
        j++;
    }

    return result;
}