以二叉链表作为二叉树的存储结构，用c语言编写以下算法并在main函数中使用： (1)统计二叉树的叶结点个数 (2)判断两棵二叉树是否相等 (3)交换二叉树每个结点的左孩子和右孩子 (4)按照层序遍历二叉树，统计树中度为1的结点个数

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

// 定义二叉树结点结构体
typedef struct TreeNode {
    int data;
    struct TreeNode *left;
    struct TreeNode *right;
} TreeNode;

// 创建二叉树结点
TreeNode *create_node(int data) {
    TreeNode *node = (TreeNode*)malloc(sizeof(TreeNode));
    node->data = data;
    node->left = NULL;
    node->right = NULL;
    return node;
}

// 统计二叉树的叶子节点个数
int count_leaf_nodes(TreeNode *root) {
    if (root == NULL) {
        return 0;
    }
    if (root->left == NULL && root->right == NULL) {
        return 1;
    }
    return count_leaf_nodes(root->left) + count_leaf_nodes(root->right);
}

// 判断两棵二叉树是否相等
int is_same_tree(TreeNode *p, TreeNode *q) {
    if (p == NULL && q == NULL) {
        return 1;
    }
    if (p == NULL || q == NULL) {
        return 0;
    }
    if (p->data != q->data) {
        return 0;
    }
    return is_same_tree(p->left, q->left) && is_same_tree(p->right, q->right);
}

// 交换二叉树每个结点的左孩子和右孩子
void swap_left_right(TreeNode *root) {
    if (root == NULL) {
        return;
    }
    TreeNode *temp = root->left;
    root->left = root->right;
    root->right = temp;
    swap_left_right(root->left);
    swap_left_right(root->right);
}

// 按照层序遍历二叉树，统计树中度为1的结点个数
int count_degree_one_nodes(TreeNode *root) {
    if (root == NULL) {
        return 0;
    }
    int count = 0;
    TreeNode *queue[1000];
    int front = 0, rear = 0;
    queue[rear++] = root;
    while (front < rear) {
        TreeNode *node = queue[front++];
        if ((node->left == NULL && node->right != NULL) || (node->left != NULL && node->right == NULL)) {
            count++;
        }
        if (node->left) {
            queue[rear++] = node->left;
        }
        if (node->right) {
            queue[rear++] = node->right;
        }
    }
    return count;
}

int main() {
    // 创建一棵二叉树
    TreeNode *root = create_node(1);
    root->left = create_node(2);
    root->right = create_node(3);
    root->left->left = create_node(4);
    root->left->right = create_node(5);
    root->right->left = create_node(6);
    root->right->right = create_node(7);

    // 统计二叉树的叶子节点个数
    int leaf_count = count_leaf_nodes(root);
    printf("叶子节点个数： %d\n", leaf_count);

    // 判断两棵二叉树是否相等
    TreeNode *root2 = create_node(1);
    root2->left = create_node(2);
    root2->right = create_node(3);
    root2->left->left = create_node(4);
    root2->left->right = create_node(5);
    root2->right->left = create_node(6);
    root2->right->right = create_node(7);
    int same = is_same_tree(root, root2);
    printf("两棵二叉树是否相等： %d\n", same);

    // 交换二叉树每个结点的左右孩子
    swap_left_right(root);
    printf("交换左右孩子后的二叉树：\n");
    printf("        %d\n", root->data);
    printf("    %d       %d\n", root->left->data, root->right->data);
    printf("  %d   %d   %d   %d\n", root->left->left->data, root->left->right->data, root->right->left->data, root->right->right->data);

    // 按照层序遍历二叉树，统计树中度为1的结点个数
    int degree_one_count = count_degree_one_nodes(root);
    printf("度为1的结点个数： %d\n", degree_one_count);
    return 0;
}