106. 从中序与后序遍历序列构造二叉树 c

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
struct TreeNode* buidl_tree(int* inorder,int head1,int n1,int* postorder,int head2,int n2){
    if(n1<=0||n2<=0) return NULL;
    struct TreeNode* root=(struct TreeNode*)malloc(sizeof(struct TreeNode));
    root->val=postorder[head2+n2-1];
    int i=head1;
    for(;i<head1+n1;i++){
        if(inorder[i]==root->val) break;
    }
    root->left=buidl_tree(inorder,head1,i-head1,postorder,head2,i-head1);
    root->right=buidl_tree(inorder,i+1,n1-i+head1-1,postorder,head2+i-head1,n2-i+head1-1);
    return root;
}

struct TreeNode* buildTree(int* inorder, int inorderSize, int* postorder, int postorderSize) {
    return buidl_tree(inorder,0,inorderSize,postorder,0,postorderSize);
}

结果：