[106] Construct Binary Tree from Inorder and Postorder Traversal

好像要再整理一下比較漂亮QQ

但是算了啦沒有很痛苦的debug就PASS了

我對自己的要求是很低的XD 已滿意 XDDDDD

/**

* Definition for a binary tree node.

* struct TreeNode {

* int val;

* struct TreeNode *left;

* struct TreeNode *right;

* };

*/

struct TreeNode* buildTree(int* inorder, int inorderSize, int* postorder, int postorderSize) {

if (inorderSize < 1)

return NULL;

if (inorderSize==1)

{

struct TreeNode* binaryT= calloc (1, sizeof(struct TreeNode));

binaryT->val = inorder[0];

return binaryT;

}

int root = postorder[postorderSize-1];

int idx=0;

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

if (inorder[i]==root)

{

idx=i;

break;

}

int lsize = idx;

int rsize = (inorderSize-idx -1);

struct TreeNode *retT= calloc (1, sizeof(struct TreeNode));

retT->val = inorder[idx];

retT->left = buildTree(inorder, lsize, postorder,lsize);

retT->right = buildTree(inorder+(idx+1), rsize, postorder+lsize,rsize);

return retT;

}