题解 | #从中序与后序遍历序列构造二叉树#

struct TreeNode* buildTree(int* inorder, int inorderLen, int* postorder, int postorderLen ) {
    // write code here
    if(inorderLen==0){
        return NULL;
    }
    
    struct TreeNode* head=(struct TreeNode*)malloc(sizeof(struct TreeNode));
    head->val=postorder[postorderLen-1];
    
    int k=0;
    int left_length=0;
    int right_length=0;
    
    while(postorder[postorderLen-1]!=inorder[k]){
        k++;
    }
    
    left_length=k;
    right_length=inorderLen-k-1;
    
    head->left=buildTree(inorder, left_length, postorder, left_length);
    head->right=buildTree(inorder+k+1, right_length, postorder+k, right_length);
    return head;
}