[Java] 배열 임의의 위치 원소 추가/제거 메서드 구현

import java.util.*;

public class Main {
	
	public static int[] insert(int idx,int num, int [] arr, int len) {
		int [] newArr = new int[len+1];
		
		for(int i=0;i<idx;i++) {
			newArr[i] = arr[i];
		}
		newArr[idx] = num;
		
		for(int i=idx,j=idx+1;i<arr.length;i++) {
			newArr[j] = arr[i];
		}
		
		return newArr;
	}
	public static int[] erase(int idx, int arr[], int len) {
		int [] newArr = new int[len-1];
		
		for(int i=0;i<idx;i++) {
			newArr[i] = arr[i];
		}
		
		for(int i=idx+1,j=idx;i<len;i++) {
			newArr[j] = arr[i];
		}
		
		return newArr;
	}
    public static void main(String[] args) {    
    	// 코드 변화 확인용
        
        int [] arr = {1,2,3};
    	int [] newArr1;
    	newArr1 = insert(2,5,arr,arr.length);
    	for(int i=0;i<newArr1.length;i++) {
    		System.out.print(newArr1[i]+" ");
    	}
    	System.out.println();
    	newArr1 = erase(2,newArr1,newArr1.length);
    	for(int i=0;i<newArr1.length;i++) {
    		System.out.print(newArr1[i]+" ");
    	}
    	
    }	
}