题目：
请完成一个函数，输入一个二叉树，输出它的镜像
struct binaryTreeNode {
int m_nValue;
binaryTreeNode* m_pLeft;
binaryTreeNode* m_pRight;
};
解法：
void mirrorBinTree(binaryTreeNode* pRoot) {
if (pRoot == 0 || (pRoot->m_pLeft == 0 && pRoot->m_pRight == 0)) {
return;
}
binaryTreeNode* tmp = pRoot->m_pLeft;
pRoot->m_pLeft = pRoot->m_pRight;
pRoot->m_pRight = tmp;
if (pRoot->m_pLeft) {
mirrorBinTree(pRoot->m_pLeft);
}
if (pRoot->m_pRight) {
mirrorBinTree(pRoot->m_pRight);
}
}
