Same Tree - 判断两棵二叉树是否相同

这个题相对来说是比较简单的，思路为：利用先序遍历来每个点进行判断

struct TreeNode {
    int value;
    TreeNode *leftTreeNode;
    TreeNode *rightTreeNode;
};

bool isSameTree(TreeNode *firstTreeNode, TreeNode *secondTreeNode) {
    if (firstTreeNode == NULL && secondTreeNode == NULL) { // 两个点都为空
        return true;
    } else if (firstTreeNode == NULL || secondTreeNode == NULL) { // 其中一个点为空
        return false;
    } else { // 两个点都不为空
        if (firstTreeNode->value == secondTreeNode->value) {
            return isSameTree(firstTreeNode->leftTreeNode, secondTreeNode->leftTreeNode) && isSameTree(firstTreeNode->rightTreeNode, secondTreeNode->rightTreeNode);
        } else {
            return false;
        }
    }
}