[Java] Merge sort 구현

import java.util.*;

public class Main {
    public static int n;
    public static int [] arr = new int[1000001];
    public static int [] tmp = new int[1000001];
    public static void merge(int st, int en){
        int mid = (st+en)/2;
        int lidx = st;
        int ridx = mid;
        for(int i=st;i<en;i++){
            if(ridx == en){
                tmp[i] = arr[lidx++];
            }else if(lidx == mid){
                tmp[i] = arr[ridx++];
            }else if(arr[lidx] <= arr[ridx]){
                tmp[i] = arr[lidx++];
            }else{
                tmp[i] = arr[ridx++];
            }
        }
        for(int i=st;i<en;i++){
            arr[i] = tmp[i];
        }

    }
    public static void merge_sort(int st, int en){
        if(st+1 == en) return;
        int mid = (st+en)/2;
        merge_sort(st, mid);
        merge_sort(mid, en);
        merge(st,en);
    }
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        n = sc.nextInt();
        for(int i=0;i<n;i++){
            arr[i] = sc.nextInt();
        }
        merge_sort(0,n);
        for(int i=0;i<n;i++){
            System.out.println(arr[i]);
        }

    }
}

 

https://blog.encrypted.gg/955

[실전 알고리즘] 0x0E강 - 정렬 I