Print binary tree in extremely small area.
When I was practicing algorithms on leetcode the other day, I found that leetcode provides a user-friendly tree-visualizer, which can convert a leetcode-style level order array to a binary tree and then display it. One amazing thing about the tree-visualizer is that it can adjust the position of each node so that the tree won't take too much space.
The tree-visualizer did help me a lot when I'was trying to solve some tree-related problems. But then I thought, why not write one by myself? So that's how this project began.
- convert a level order array (leetcode-style or typical) to a binary tree
- print a binary tree in extremely small area by calculating the position of each node dynamically
- print any Class in addition to Integer
This project has been released to maven repository, simply add dependency as below:
<dependency>
<groupId>com.github.afkbrb</groupId>
<artifactId>binary-tree-printer</artifactId>
<version>1.0.0</version>
</dependency>Print random BST.
BTPrinter.printRandomBST(100, 100); 38
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28 82
/ \ / \
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5 31 / \
/ \ / \ / \
/ \ 30 36 / \
/ \ / / \ / \
/ \ 29 33 37 / \
/ \ / \ / \
/ \ 32 35 65 95
1 14 / / \ / \
/ \ / \ 34 / \ 94 97
0 2 / \ / \ / / \
\ 12 24 / \ 93 96 98
3 / \ / \ / \ / \
\ 9 13 16 25 / \ 84 99
4 / \ / \ \ / \ / \
7 10 15 23 26 59 74 83 86
/ \ \ / \ / \ / \ / \
6 8 11 22 27 56 60 73 76 85 91
/ / \ \ / / \ / \
20 / \ 61 67 75 79 88 92
/ \ 40 58 \ / \ / \ / \
18 21 / \ / 62 66 72 78 80 87 89
/ \ 39 54 57 \ / / \ \
17 19 / \ 64 69 77 81 90
50 55 / / \
/ \ 63 68 70
/ \ \
/ \ 71
47 53
/ \ /
/ \ 52
42 49 /
/ \ / 51
41 43 48
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46
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45
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44
Print tree from leetcode-style level order array, '#' means a path terminator where no node exists below.
BTPrinter.printTree("1,2,3,4,5,#,#,6,7,8,1,#,#,#,#,#,#,2,3,4,5,6,7,8,9,10,11,12,13,14,15"); 1
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4 5
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6 7 8 1
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2 3
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4 5 6 7
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8 9 10 11 12 13 14 15
Print tree from typical level order array.
BTPrinter.printTreeLevelOrder("1,#,2,#,#,#,3,#,#,#,#,#,#,#,4");1
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Print objects.
BTPrinter.printTree("root", 2, 333, null, null, null, new Foo(), null, new Foo(), null, "end"); root
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2 333
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com.github.afkbrb.btp.Foo@646d64ab
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com.github.afkbrb.btp.Foo@59e5ddf
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end
Notice that we can override Foo's toString method, so that the output won't be that ugly.
For more examples, see Example and Test.
| Method | Description |
|---|---|
| printTree(String s) | Print a tree from a leetcode-style level order expression. '#' means a path terminator where no node exists below. |
| printTreeLevelOrder(String s) | Print a tree from a typical level order expression. '#' means null. |
| printTree(Object... objs) | Print a tree from a leetcode-style level order array. Notice that you can input instances with different types at the same time, the algorithm will always work. The value of each tree node will equal to the String value of the corresponding obj, i.e. String.valueOf(obj). A null object means a path terminator where no node exists below. |
| printTreeLevelOrder(Object... objs) | Print a tree from a typical level order array. Notice that you can input instances of different Classes at the same time, the algorithm will always work. The value of each tree node will equal to the String value of the corresponding obj, i.e. String.valueOf(obj). |
| printRandomBST(int n, int bound) | Print a random binary search tree. n is the node count of the BST, bound is the bound of the val of a tree node. Both n and bound must be positve, and n shouldn't be larger than bound. |
Feel free to use it.
Issues and PRs are welcomed!
Stars are welcomed, too 😄!