C语言实现树结构并打印节点下层节点

#include <stdio.h> #include <stdlib.h> #include <string.h>

typedef struct Node { char val; struct Node *child; struct Node *sibling; } Node;

Node *createNode(char val) { Node *newNode = (Node *)malloc(sizeof(Node)); newNode->val = val; newNode->child = NULL; newNode->sibling = NULL; return newNode; }

Node *findNode(Node *root, char val) { if (root == NULL) { return NULL; } if (root->val == val) { return root; } Node *childResult = findNode(root->child, val); if (childResult != NULL) { return childResult; } Node *siblingResult = findNode(root->sibling, val); if (siblingResult != NULL) { return siblingResult; } return NULL; }

void printChildren(Node *node) { Node *child = node->child; while (child != NULL) { printf('%c\n', child->val); child = child->sibling; } }

int main() { int n; scanf("%d", &n);

Node *root = NULL;
Node **nodes = (Node **)malloc(n * sizeof(Node *));

for (int i = 0; i < n; i++) {
    char val, parent;
    scanf(" %c %c", &val, &parent);
    
    if (root == NULL) {
        root = createNode(parent);
        nodes[i] = root;
    }
    
    Node *parentNode = findNode(root, parent);
    if (parentNode == NULL) {
        printf("Invalid input: parent node not found\n");
        return 0;
    }
    
    Node *newNode = createNode(val);
    if (parentNode->child == NULL) {
        parentNode->child = newNode;
    } else {
        Node *sibling = parentNode->child;
        while (sibling->sibling != NULL) {
            sibling = sibling->sibling;
        }
        sibling->sibling = newNode;
    }
    
    nodes[i] = newNode;
}

char target;
scanf(" %c", &target);

Node *targetNode = findNode(root, target);
if (targetNode == NULL) {
    printf("Invalid input: target node not found\n");
    return 0;
}

printChildren(targetNode);

return 0;

}