2025-01-21 霍夫曼树

src/dataANDcalc/java/tree/HuffmanTree.java

@@ -0,0 +1,120 @@
+package tree;
+
+public class HuffmanTree {
+
+    private TreeNode[] arr;
+
+    private TreeNode huffTree;
+
+    public HuffmanTree(int[] arr){
+        this.arr = new TreeNode[arr.length];
+        for(int i=0; i<arr.length; i++){
+            this.arr[i] = new TreeNode(arr[i]);
+        }
+        sort();
+    }
+
+    /**
+     * 创建霍夫曼树
+     */
+    public void createHuffTree(){
+        while(true){
+            TreeNode left = arr[0];
+            TreeNode right = arr[1];
+            TreeNode root = new TreeNode(arr[0].node + arr[1].node);
+            root.createHuffTreeNode(left, right);
+            if(arr.length == 2){
+                huffTree = root;
+                break;
+            }
+            createNodeArr(2, arr.length - 1, root);
+            sort();
+        }
+    }
+
+    /**
+     * 剔除掉原数组的头两个结点并加入新生成的霍夫曼节点，重新创建数组
+     * @param left
+     * @param right
+     * @param node
+     */
+    public void createNodeArr(int left, int right, TreeNode node){
+        TreeNode[] tempArr = new TreeNode[right - left + 2];
+        for(int i=0; i<tempArr.length - 1; i++){
+            tempArr[i] = arr[left];
+            left++;
+        }
+        tempArr[tempArr.length - 1] = node;
+        arr = tempArr;
+    }
+
+    /**
+     * 用希尔排序对结点数组进行排序
+     */
+    private void sort(){
+        int gap = arr.length;
+        while(true){
+            // 每次步长为原来步长的一半，初始的步长为排序数组长度的一半
+            gap = gap/2;
+            // 分组进行插入排序
+            for (int i = gap; i <arr.length; i++){
+                // 获取本轮需要插入的数，并初始化一个下标为排序数组的最后一个下标
+                TreeNode temp = arr[i];
+                int index = i-gap;
+                // 当下标小于0就意味着已经完成本轮找位置的过程
+                // 如果当前插入的数小于下标指向的数,需要将当前下标数往后移动移位gap，并且下标要继续往前移动gap位
+                // 直到下标小于0或者当前插入数大于下标位置的数
+                while (index >=0 && temp.node < arr[index].node){
+                    arr[index+gap] = arr[index];
+                    index -= gap;
+                }
+                //将当前数插入到下标+gap的位置
+                arr[index+gap] = temp;
+            }
+            if (gap == 1){
+                break;
+            }
+        }
+    }
+
+    private void middleIterator(TreeNode treeNode){
+        if(treeNode == null){
+            System.out.println("当前节点为空");
+            return;
+        }
+
+        if (treeNode.left!= null){
+            middleIterator(treeNode.left);
+        }
+
+        System.out.println(treeNode.node);
+
+        if (treeNode.right!= null){
+            middleIterator(treeNode.right);
+        }
+    }
+
+    public static class TreeNode{
+        private int node;
+
+        private TreeNode left;
+
+        private TreeNode right;
+
+        public TreeNode(int node){
+            this.node = node;
+        }
+
+        private void createHuffTreeNode(TreeNode left, TreeNode right){
+            this.left = left;
+            this.right = right;
+        }
+    }
+
+    public static void main(String[] args) {
+        int[] arr = new int[]{13,7,8,3,29,6,1};
+        HuffmanTree huffmanTree = new HuffmanTree(arr);
+        huffmanTree.createHuffTree();
+        huffmanTree.middleIterator(huffmanTree.huffTree);
+    }
+}