归并排序

归并排序是分治思想的一种实现。

function mergeSort(arr){    if(arr.length <= 1) return arr;    var mid = Math.floor(arr.length/2);    var leftArr = arr.slice(0, mid);    var rightArr = arr.slice(mid);    return merge(mergeSort(leftArr), mergeSort(rightArr));}function merge(leftArr, rightArr){    var result = [];    while(leftArr.length && rightArr.length){        if(leftArr[0] < rightArr[0]){            result.push(leftArr.shift());        }else{            result.push(rightArr.shift());        }    }    return result.concat(leftArr, rightArr);}console.log('mergeSort', mergeSort([4, 7, 2, 1, 5, 3, 8, 6]));