sleepingraven / AlgorithmNote

Practical utilities in algorithm learning / OJ accepting.

Note Structure

• draft OJ 代码编辑区域
• note 笔记/练习
  • demo，helloworld 一些题目和基本数据结构的练习
  • huffman 用 Huffman 编码实现文件压缩
  • practice 常见/常用算法实现
• util 工具/模板
  • ac，advanced 常用数据结构/工具类
  • common，function，primitive 基础工具类
  • datastructure 二叉树、链表的生成和格式化工具

1. note

huffman

压缩/解压文件的程序实现

demo:

String srcPath = "D:/new Text Document.pdf";
StoreWay storeWay = new CodeCustom();
CodingMethod codingMethod = new DefaultCodingMethod();

Compressor compressor = new Compressor(1);
String destPath = compressor.compress(srcPath, storeWay, codingMethod);
Decompressor decompressor = new Decompressor();
String decompressPath = decompressor.decompress(destPath, codingMethod);

System.out.println(destPath);
System.out.println(decompressPath);

output:

……
用时：        834ms


D:\new Text Document.h_tar
D:\new Text Document(1).pdf

practice

CircularVector

用来在矩阵中以螺旋的顺序生成一组下标

demo:

final int n = 4;
int[][] matrix = new int[n][n];
CircularVector cv = new CircularVector(0, n - 1, 0, n - 1);
for (int i = 1; i <= n * n; i++) {
    matrix[cv.x()][cv.y()] = i;
    cv.next();
}

String str = Arrays.stream(matrix).map(Arrays::toString).collect(Collectors.joining("\n"));
System.out.println(str);

output:

[1, 2, 3, 4]
[12, 13, 14, 5]
[11, 16, 15, 6]
[10, 9, 8, 7]

2. util

ac

DataGenerator

用来

• 根据数组创建二叉树、链表
• 将字符串解析成数组

demo:

int[][] matrix = DataGenerator.parseIntArray("[[1,2,3],[4,5,6],[7,8,9]]", int[][].class);

String str = Arrays.stream(matrix).map(Arrays::toString).collect(Collectors.joining("\n"));
System.out.println(str);

output:

[1, 2, 3]
[4, 5, 6]
[7, 8, 9]

datastructure

用来

• 生成二叉树、链表
• 格式化二叉树、链表

demo:

final int n = 31;
Integer[] a = IntStream.range(1, n + 1).boxed().toArray(i -> new Integer[n]);
TreeNode treeNode = DataGenerator.buildTree(a);

String str = treeNode.toString();
System.out.println(str);

output:

                              1
                      /               \
              2                               3
          /       \                       /       \
      4               5               6               7
    /   \           /   \           /   \           /   \
  8       9      10      11      12      13      14      15
 / \     / \     / \     / \     / \     / \     / \     / \
16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31