请实现一个函数,用来判断一颗二叉树是不是对称的。
注意,如果一个二叉树同此二叉树的镜像是同样的,定义其为对称的
其实就是层次遍历,这个我们在我之前的一篇博客里面将的很清楚了
其中调试的时候使用了
剑指Offer--006-重构二叉树来辅助我们通过前序和中序遍历的序列来生成二叉树
直接贴代码,只需要直接将我们层次遍历输出过程,变成将输入压入vector中即可
#include <iostream>
#include <vector>
#include <deque>
#include <queue>
using namespace std;
#define __tmain main
#ifdef __tmain
#define debug cout
#else
#define debug 0 && cout
#endif // __tmain
#define undebug 0 && cout
#ifdef __tmain
struct TreeNode
{
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x = 0)
:val(x), left(NULL), right(NULL)
{
}
};
#endif // __tmain
class Solution
{
vector< vector<int> > res;
vector<int> curr;
public:
vector< vector<int> > Print(TreeNode *root)
{
LevelOrder(root);
LevelOrderDev(root);
LevelOrderUsePoint(root);
LevelOrderUseSize(root);
LevelOrderUseEnd(root);
return this->res;
}
int PrintLevel(TreeNode *root, int level)
{
if(root == NULL || level < 0)
{
return 0;
}
else if(level == 0)
{
debug <<root->val;
curr.push_back(root->val); /// add for currult in vector
return 1;
}
else
{
return PrintLevel(root->left, level - 1) + PrintLevel(root->right, level - 1);
}
}
void LevelOrder(TreeNode *root)
{
curr.clear( ); /// add for currult in vector
res.clear( );
if(root == NULL)
{
return;
}
for(int level = 0; ; level++)
{
if(PrintLevel(root, level) == 0)
{
break;
}
res.push_back(curr);
curr.clear( );
debug <<endl;
}
}
//////////////////////////
//////////////////////////
void LevelOrderDev(TreeNode *root)
{
curr.clear( ); /// add for currult in vector
res.clear( );
if(root == NULL)
{
return ;
}
deque<TreeNode *> qFirst, qSecond;
qFirst.push_back(root);
while(qFirst.empty( ) != true)
{
while (qFirst.empty( ) != true)
{
TreeNode *temp = qFirst.front( );
qFirst.pop_front( );
debug << temp->val;
curr.push_back(temp->val); /// add for currult in vector
if (temp->left != NULL)
{
qSecond.push_back(temp->left);
}
if (temp->right != NULL)
{
qSecond.push_back(temp->right);
}
}
debug << endl;
res.push_back(curr);
curr.clear( );
qFirst.swap(qSecond);
}
}
//////////////////////////
//////////////////////////
void LevelOrderUsePoint(TreeNode *root)
{
curr.clear( ); /// add for currult in vector
res.clear( );
if(root == NULL)
{
return ;
}
vector<TreeNode*> vec;
vec.push_back(root);
int cur = 0;
int end = 1;
while (cur < vec.size())
{
end = vec.size();
while (cur < end)
{
debug << vec[cur]->val;
curr.push_back(vec[cur]->val); /// add for currult in vector
if (vec[cur]->left != NULL)
{
vec.push_back(vec[cur]->left);
}
if (vec[cur]->right != NULL)
{
vec.push_back(vec[cur]->right);
}
cur++;
}
res.push_back(curr);
curr.clear( );
debug << endl;
}
}
void LevelOrderUseSize(TreeNode *root)
{
curr.clear( ); /// add for currult in vector
res.clear( );
if(root == NULL)
{
return ;
}
int parentSize = 1, childSize = 0;
TreeNode *temp = NULL;
queue<TreeNode *> q;
q.push(root);
while(q.empty( ) != true)
{
temp = q.front( );
debug <<temp->val;
curr.push_back(temp->val); /// add for currult in vector
q.pop( );
if (temp->left != NULL)
{
q.push(temp->left);
childSize++;
}
if (temp->right != NULL)
{
q.push(temp->right);
childSize++;
}
parentSize--;
if (parentSize == 0)
{
parentSize = childSize;
childSize = 0;
res.push_back(curr);
curr.clear( );
debug << endl;
}
}
}
void LevelOrderUseEnd(TreeNode *root)
{
curr.clear( ); /// add for currult in vector
res.clear( );
if(root == NULL)
{
return ;
}
queue<TreeNode *> q;
q.push(root);
q.push(NULL);
while(q.empty( ) != true)
{
TreeNode* node = q.front();
q.pop();
if (node)
{
debug <<node->val;
curr.push_back(node->val); /// add for currult in vector
if (node->left != NULL)
{
q.push(node->left);
}
if (node->right != NULL)
{
q.push(node->right);
}
}
else if (q.empty( ) != true)
{
q.push(NULL);
res.push_back(curr);
curr.clear( );
debug << endl;
}
}
if(curr.size() != 0)
{
res.push_back(curr);
curr.clear( );
cout <<endl;
}
}
};
int __tmain( )
{
TreeNode tree[7];
tree[0].val = 8;
tree[0].left = &tree[1];
tree[0].right = &tree[2];
tree[1].val = 6;
tree[1].left = &tree[3];
tree[1].right = &tree[4];
tree[2].val = 6;
tree[2].left = &tree[5];
tree[2].right = &tree[6];
tree[3].val = 5;
tree[3].left = NULL;
tree[3].right = NULL;
tree[4].val = 7;
tree[4].left = NULL;
tree[4].right = NULL;
tree[5].val = 7;
tree[5].left = NULL;
tree[5].right = NULL;
tree[6].val = 5;
tree[6].left = NULL;
tree[6].right = NULL;
Solution solu;
vector< vector<int> > res = solu.Print(tree);
for(int i = 0; i < res.size( ); i++)
{
for(int j = 0; j < res[i].size( ); j++)
{
cout <<res[i][j];
}
cout <<endl;
}
return 0;
}