[105] Construct Binary Tree from Preorder and Inorder Traversal

啊～我到底寫了什麼 Orz

給一個 inorder 跟 preorder ，把它們的binary tree 做出來

怎麼拿摸難！！！！！！

沒看解答完全不會寫（攤手）

糟了一個糕

/**

* Definition for a binary tree node.

* struct TreeNode {

* int val;

* struct TreeNode *left;

* struct TreeNode *right;

* };

*/

int find(int* inorder, int inorderSize, int root)

{

int index=0;

for (int i=0;i<inorderSize;i++)

{

if (inorder[i]==root)

return i;

}

return -1;

}

struct TreeNode* buildTree(int* preorder, int preorderSize, int* inorder, int inorderSize){

if (preorderSize<=0 || inorderSize <=0)

return NULL;

struct TreeNode *root = malloc (sizeof (struct TreeNode));

root->val = preorder[0];

int rootIndex = find(inorder, inorderSize, preorder[0]);

root->left = buildTree(preorder+1, rootIndex, inorder, rootIndex);

root->right = buildTree(preorder+rootIndex+1, inorderSize - rootIndex - 1, inorder+rootIndex+1, inorderSize - rootIndex - 1);

return root;

}