Leetcode#106 Construct Binary Tree from Inorder and Postorder Traversal

原题地址

二叉树基本操作

[       ]O[              ]

[       ][              ]O

代码：

TreeNode *restore(vector<int> &inorder, vector<int> &postorder, int ip, int pp, int len) {
  if (len == 0)
    return NULL;

  TreeNode *node = new TreeNode(postorder[pp + len - 1]);

  if (len == 1)
    return node;

  int leftLen = 0;
  while (inorder[ip + leftLen] != postorder[pp + len - 1])
    leftLen++;
  node->left = restore(inorder, postorder, ip, pp, leftLen);
  node->right = restore(inorder, postorder, ip + leftLen + 1, pp + leftLen, len - leftLen - 1);

  return node;
}

TreeNode *buildTree(vector<int> &inorder, vector<int> &postorder) {
  return restore(inorder, postorder, 0, 0, inorder.size());
}