[DP] 백준 - 1,2,3 더하기

-문제

https://www.acmicpc.net/problem/9095

9095번: 1, 2, 3 더하기

 

-자바

package dp;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class Plus123_1 {
	private static BufferedWriter bw = 
			new BufferedWriter( new OutputStreamWriter(System.out));
	private static int t;		//테스트케이스 개수
	private static int n;		//주어지는 정수
	private static int[] arr;	//정수 n이 만들어지는 개수가 담길 배열
	
	public static void main(String[] args) throws NumberFormatException, IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		t = Integer.parseInt( br.readLine() );
		
		arr = new int[11];
		arr[1] = 1;
		arr[2] = 2;
		arr[3] = 4;
		
		for( int i=0; i<t; i++ ) {
			n = Integer.parseInt( br.readLine() );
			
			for( int j=4; j<=n; j++ ) {
				arr[j] = arr[j-1] + arr[j-2] + arr[j-3];
			}
			
			bw.write( arr[n] + "\n" );
			bw.flush();
		}
		
		bw.close();
		br.close();
	}
}

 

 

-파이썬

t = int( input() )

arr = [0] * 11

for i in range(t):
    n = int( input() )
    
    arr[1] = 1
    arr[2] = 2
    arr[3] = 4
    
    for j in range(4, n+1):
        arr[j] = arr[j-1] + arr[j-2] + arr[j-3]
    
    print( arr[n] )