백준알고리즘 10844번 쉬운 계단 수

백준알고리즘

https://www.acmicpc.net/problem/10844

생각보다 어려웠다. 소스는 첨부하나 설명은 적지 못하겠다. 그림그려야되니깐

import java.util.Scanner;

public class Main {
    
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int value = Integer.parseInt(scan.nextLine().trim());
        
        long memoArray[][] = new long[value][10];
        memoArray[0][0] = 0;
        memoArray[0][1] = 1;
        memoArray[0][2] = 1;
        memoArray[0][3] = 1;
        memoArray[0][4] = 1;
        memoArray[0][5] = 1;
        memoArray[0][6] = 1;
        memoArray[0][7] = 1;
        memoArray[0][8] = 1;
        memoArray[0][9] = 1;
        
        long result[] = new long[value];
        result[0] = 9;
        
        for(int i=1;i<value; i++) {
            long total = 0;
            
            for(int j=0; j<10; j++) {
                if(j==0) {
                    memoArray[i][j] = memoArray[i-1][j+1] % 1000000000;
                    total += memoArray[i][j];
                    continue;
                }
                
                if(j > 0 && j < 9) {
                    memoArray[i][j] = (memoArray[i-1][j-1] + memoArray[i-1][j+1]) % 1000000000;
                    total += memoArray[i][j];
                    continue;
                }
                
                if(j==9) {
                    memoArray[i][j] = memoArray[i-1][j-1] % 1000000000;
                    total += memoArray[i][j];
                    continue;
                }
            }
            
            result[i] = total;
        }
        System.out.println(result[value -1] % 1000000000);
    }
}