The 4th Blue Bridge Cup Javab Group Provincial Tournament - Revitalizing China

Topic description

Xiaoming participated in the fun gain of the school, one of which is: jumping.

Painted some plaids on the ground, write a word in each lattice, as shown below:

From me
I am making a revitalization
Start in revitalization
Vain

When the game, first stand in the upper left corner of the "from" on the lattice, you can jump to adjacent plaids laterally or longitudinally, but you cannot jump to the diagonal lattice or other location. Always jump to the word "Hua" word.

The route that is required to jump is just a word "starting to revitalize China".

Please help Xiao Ming calculate how many possible jumping routes?

The answer is an integer, please submit the number directly via the browser.
Note: Do not submit a solution process, or other auxiliary instructions.

Solution process

Because the data structure is not good ... So this topic did not think of using deep search ideas (DFS), but tried to use violent solution to solve the problem, try to use a two-dimensional array, use 1, 2, 3 , 4 ... nine numbers represent nine Chinese characters, then find it in order ... However, it is difficult to achieve ...
Then, by analyzing the recursive writing method of depth search, some depth search related content is checked.
Link:Depth priority search algorithm
Currently, only the example of this big, is mainly how to construct a four-digit number of each digit in the four digits of 1, 2, 3, and 4.
(PS: I feel uncomfortable ... I will find some big blog later.)

Point

return dfs(i + 1, j) + dfs(i, j + 1);
I feel that this recursive is the core content, because the data structure is not good ... so I understand the thoroughly spending a good job ...
First, you can observe the pictures in the topic, you can know that the route is only right and lower, and as long as any of the options have reached the end, it can be determined as a choice. I don't understand why I've detrimented endless ways ...

Code

public class Main {
 
	public static void main(String[] args) {
		int ans = 0;
		ans = dfs(0, 0);
		System.out.println(ans);
	}
 
	public static int dfs(int i, int j) {
		if (i == 3 || j == 4) {
			return 1;
		}
		return dfs(i + 1, j) + dfs(i, j + 1);
	}
}

I feel that I have a lot of simple things.
I slept!