序列化和反序列化 N 叉树

给定一个 N 叉树，其中每个节点最多有 N 个孩子。如何序列化和反序列化？序列化是将树存储在一个文件中，以便以后可以恢复它。必须保持树的结构。反序列化是从文件中读回树。
这个帖子主要是下面帖子的延伸。
序列化和反序列化二叉树

在 N 叉树中，没有指定的左右孩子。 N 叉树由每个节点存储一个数组或子指针列表来表示。

这个想法是为每个节点存储一个“孩子结束”标记。下图显示了序列化，其中 ')' 用作子标记的结尾。

以下是上述想法的 C++ 实现。

C++

// A C++ Program serialize and deserialize an N-ary tree
#include
#define MARKER ')'
#define N 5
using namespace std;
 
// A node of N-ary tree
struct Node {
   char key;
   Node *child[N];  // An array of pointers for N children
};
 
// A utility function to create a new N-ary tree node
Node *newNode(char key)
{
    Node *temp = new Node;
    temp->key = key;
    for (int i = 0; i < N; i++)
        temp->child[i] = NULL;
    return temp;
}
 
// This function stores the given N-ary tree in a file pointed by fp
void serialize(Node *root, FILE *fp)
{
    // Base case
    if (root == NULL) return;
 
    // Else, store current node and recur for its children
    fprintf(fp, "%c ", root->key);
    for (int i = 0; i < N && root->child[i]; i++)
         serialize(root->child[i],  fp);
 
    // Store marker at the end of children
    fprintf(fp, "%c ", MARKER);
}
 
// This function constructs N-ary tree from a file pointed by 'fp'.
// This function returns 0 to indicate that the next item is a valid
// tree key. Else returns 0
int deSerialize(Node *&root, FILE *fp)
{
    // Read next item from file. If there are no more items or next
    // item is marker, then return 1 to indicate same
    char val;
    if ( !fscanf(fp, "%c ", &val) || val == MARKER )
       return 1;
 
    // Else create node with this item and recur for children
    root = newNode(val);
    for (int i = 0; i < N; i++)
      if (deSerialize(root->child[i], fp))
         break;
 
    // Finally return 0 for successful finish
    return 0;
}
 
// A utility function to create a dummy tree shown in above diagram
Node *createDummyTree()
{
    Node *root = newNode('A');
    root->child[0] = newNode('B');
    root->child[1] = newNode('C');
    root->child[2] = newNode('D');
    root->child[0]->child[0] = newNode('E');
    root->child[0]->child[1] = newNode('F');
    root->child[2]->child[0] = newNode('G');
    root->child[2]->child[1] = newNode('H');
    root->child[2]->child[2] = newNode('I');
    root->child[2]->child[3] = newNode('J');
    root->child[0]->child[1]->child[0] = newNode('K');
    return root;
}
 
// A utility function to traverse the constructed N-ary tree
void traverse(Node *root)
{
    if (root)
    {
        printf("%c ", root->key);
        for (int i = 0; i < N; i++)
            traverse(root->child[i]);
    }
}
 
// Driver program to test above functions
int main()
{
    // Let us create an N-ary tree shown in above diagram
    Node *root = createDummyTree();
 
    // Let us open a file and serialize the tree into the file
    FILE *fp = fopen("tree.txt", "w");
    if (fp == NULL)
    {
        puts("Could not open file");
        return 0;
    }
    serialize(root, fp);
    fclose(fp);
 
    // Let us deserialize the stored tree into root1
    Node *root1 = NULL;
    fp = fopen("tree.txt", "r");
    deSerialize(root1, fp);
 
    printf("Constructed N-Ary Tree from file is \n");
    traverse(root1);
 
    return 0;
}

输出：

Constructed N-Ary Tree from file is
A B E F K C D G H I J