https://github.com/umer0586/depth-first-search

Depth first search algorithm and java implementation
https://github.com/umer0586/depth-first-search

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Depth first search algorithm and java implementation

• Host: GitHub
• URL: https://github.com/umer0586/depth-first-search
• Owner: umer0586
• License: gpl-3.0
• Created: 2018-11-18T11:29:11.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2018-11-18T11:59:24.000Z (about 6 years ago)
• Last Synced: 2024-09-14T02:45:07.228Z (4 months ago)
• Language: Java
• Size: 41 KB
• Stars: 0
• Watchers: 0
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# DEPTH FIRST SEARCH

Depth first search algorithm and java implementation

# ALGORITHM



begin 

open := [Start];

closed := [ ];

 while open # [ ] do

 begin

 remove leftmost state from open, call it X; 

 if X is a goal then return SUCCESS

   else begin

        generate children of X;

        put X on closed; 

        discard children of X if already on open or closed;

        put remaining children on left end of open

    end 

  end; 

 return FAIL 

end. 



# Given tree

![Tree](https://github.com/umer0586/depth-first-search/blob/master/tree.png)

# Applying alogrithm on above tree

finding goal **G** from root **A**


1. open = [A]; closed = [ ] 

2. open = [B,C,D]; closed = [A] 

3. open = [E,F,C,D]; closed = [B,A] 

4. open = [K,L,F,C,D]; closed = [E,B,A]

5. open = [S,L,F,C,D]; closed = [K,E,B,A]

6. open = [L,F,C,D]; closed = [S,K,E,B,A] 

7. open = [T,F,C,D]; closed = [L,S,K,E,B,A] 

8. open = [F,C,D]; closed = [T,L,S,K,E,B,A]

9. open = [M,C,D], as L is already on closed; closed = [F,T,L,S,K,E,B,A] 

10. open = [C,D]; closed = [M,F,T,L,S,K,E,B,A] 

11. open = [G,H,D]; closed = [C,M,F,T,L,S,K,E,B,A] 

goal G found



# Java example

```java

		Tree tree = new Tree();

```	

![Tree](https://github.com/umer0586/depth-first-search/blob/master/tree.png)

    

```java		

		tree.addParentChildren('A','B','C','D'); // A is parent of B, C and D

		tree.addParentChildren('B', 'E','F'); // B is parent of E and F

		tree.addParentChildren('E', 'K','L');

		tree.addParentChildren('K', 'S');

		tree.addParentChildren('L', 'T');

		tree.addParentChildren('F', 'L','M');

		tree.addParentChildren('C', 'G','H');

		tree.addParentChildren('G', 'N');

		tree.addParentChildren('H', 'O','P');

		tree.addParentChildren('D', 'I','J');

		tree.addParentChildren('I', 'P','Q');

		tree.addParentChildren('P', 'U');

		tree.addParentChildren('J', 'R');

		

		//Now for Terminal or leaf nodes no children are specified

		tree.addParentChildren('S'); 

		tree.addParentChildren('T');

		tree.addParentChildren('M');

		tree.addParentChildren('N');

		tree.addParentChildren('O');

		tree.addParentChildren('U');

		tree.addParentChildren('Q');

		tree.addParentChildren('R');

		

	

		tree.findGoal('G','A'); // find goal 'G' from 'A'

```

# Console output


Console Output:-

X = A open = [A] close = []

X = B open = [B, C, D] close = [A]

X = E open = [E, F, C, D] close = [A, B]

X = K open = [K, L, F, C, D] close = [A, B, E]

X = S open = [S, L, F, C, D] close = [A, B, E, K]

X = L open = [L, F, C, D] close = [A, B, S, E, K]

X = T open = [T, F, C, D] close = [A, B, S, E, K, L]

X = F open = [F, C, D] close = [A, B, S, T, E, K, L]

X = M open = [M, C, D] close = [A, B, S, T, E, F, K, L]

X = C open = [C, D] close = [A, B, S, T, E, F, K, L, M]

X = G open = [G, H, D] close = [A, B, S, C, T, E, F, K, L, M]

goal : G found