写一个c语言代码按先序遍历序列建立一个二叉树的二叉链表，统计二叉树中叶子结点个数和二叉树的深度。

以下是代码实现：

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

// 定义二叉树结构体
struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
};

// 创建二叉树
struct TreeNode* createTree(int *preorder, int start, int end) {
    if (start > end) {
        return NULL;
    }

    // 创建根节点
    struct TreeNode* root = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    root->val = preorder[start];
    root->left = NULL;
    root->right = NULL;

    int i;
    for (i = start; i <= end; i++) {
        if (preorder[i] > root->val) {
            break;
        }
    }

    // 递归创建左子树和右子树
    root->left = createTree(preorder, start + 1, i - 1);
    root->right = createTree(preorder, i, end);

    return root;
}

// 统计叶子节点个数
int countLeafNodes(struct TreeNode* root) {
    if (root == NULL) {
        return 0;
    }

    if (root->left == NULL && root->right == NULL) {
        return 1;
    }

    return countLeafNodes(root->left) + countLeafNodes(root->right);
}

// 计算二叉树的深度
int maxDepth(struct TreeNode* root) {
    if (root == NULL) {
        return 0;
    }

    int leftDepth = maxDepth(root->left);
    int rightDepth = maxDepth(root->right);

    return leftDepth > rightDepth ? leftDepth + 1 : rightDepth + 1;
}

int main() {
    int preorder[] = {5, 3, 2, 4, 7, 6, 8};
    int len = sizeof(preorder) / sizeof(preorder[0]);

    // 创建二叉树
    struct TreeNode* root = createTree(preorder, 0, len - 1);

    // 统计叶子节点个数
    int leafNodes = countLeafNodes(root);
    printf("叶子结点个数：%d\n", leafNodes);

    // 计算二叉树的深度
    int depth = maxDepth(root);
    printf("二叉树的深度：%d\n", depth);

    return 0;
}

这里我们使用了先序遍历来创建二叉树，然后分别统计叶子节点个数和二叉树的深度。