题解 | #归并排序-最小的K个数#

function GetLeastNumbers_Solution(input, k)
{
    // write code here
    if(k>input.length){return [];}
    let ans = merge(input);
    //console.log('jj'+ans);
    return ans.slice(0,k);
}
function merge(arr){
    if(arr.length < 2) return arr;
    let mid = Math.floor(arr.length / 2);
    return mergetwo(merge(arr.slice(0,mid)),merge(arr.slice(mid)));
}
function mergetwo(arr1,arr2){
    let ans = [];
    let len = arr1.length + arr2.length;
    for(let i = 0,j=0,index = 0;index<len;index++){
        if(i>=arr1.length){
            ans[index] = arr2[j++];
        }else if(j>=arr2.length){
            ans[index] = arr1[i++];
        }else if(arr1[i]<=arr2[j]){
            ans[index] = arr1[i++];
        }else{
            ans[index] = arr2[j++];
        }
    }
    //console.log(ans);
    return ans;
}
module.exports = {
    GetLeastNumbers_Solution : GetLeastNumbers_Solution
};