用c语言写二叉树求根结点到叶子结点的最长距离

下面是用C语言实现二叉树求根节点到叶子节点的最长距离的示例代码：

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

typedef struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
} TreeNode;

int maxDepth(TreeNode *root) {
    if (!root) {
        return 0;
    }
    int left_depth = maxDepth(root->left);
    int right_depth = maxDepth(root->right);
    return left_depth > right_depth ? left_depth + 1 : right_depth + 1;
}

int maxDistance(TreeNode *root) {
    if (!root) {
        return 0;
    }
    int left_depth = maxDepth(root->left);
    int right_depth = maxDepth(root->right);
    int left_distance = maxDistance(root->left);
    int right_distance = maxDistance(root->right);
    return left_depth + right_depth > left_distance ? (left_depth + right_depth > right_distance ? left_depth + right_depth : right_distance) : (left_distance > right_distance ? left_distance : right_distance);
}

int main() {
    // 创建二叉树
    TreeNode *root = (TreeNode *)malloc(sizeof(TreeNode));
    root->val = 1;
    root->left = (TreeNode *)malloc(sizeof(TreeNode));
    root->left->val = 2;
    root->left->left = NULL;
    root->left->right = (TreeNode *)malloc(sizeof(TreeNode));
    root->left->right->val = 3;
    root->left->right->left = NULL;
    root->left->right->right = NULL;
    root->right = (TreeNode *)malloc(sizeof(TreeNode));
    root->right->val = 4;
    root->right->left = (TreeNode *)malloc(sizeof(TreeNode));
    root->right->left->val = 5;
    root->right->left->left = NULL;
    root->right->left->right = NULL;
    root->right->right = NULL;

    // 计算最长距离
    int max_distance = maxDistance(root);
    printf("The max distance of the binary tree is: %d\n", max_distance);

    return 0;
}

其中，TreeNode是二叉树的节点结构体，maxDepth函数用于计算二叉树的深度，maxDistance函数用于计算二叉树的最长距离。main函数中创建了一个二叉树，并计算了它的最长距离。