105.construct-binary-tree-from-preorder-and-inorder-traversal.c

/*
 * @lc app=leetcode id=105 lang=c
 *
 * [105] Construct Binary Tree from Preorder and Inorder Traversal
 */

// @lc code=start
struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
};

struct TreeNode* buildTree(int* preorder, int preorderSize, int* inorder, int inorderSize){
    // first val in pre is root

    //bc
    if

}
// @lc code=end

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
typedef struct TreeNode TreeNode;

TreeNode *build(int *preorder, int *inorder, int *rootIndex, int inorderLeft, int inorderRight)
{
    if (inorderLeft >= inorderRight)
    {
        return NULL;
    }

    TreeNode *root = (TreeNode *)malloc(sizeof(TreeNode));
    root->val = preorder[*rootIndex];
    int mid = 0;

    // Finding mid
    for (size_t i = inorderLeft; i < inorderRight; i++)
    {
        if (inorder[i] == preorder[*rootIndex])
        {
            mid = i;
            break;
        }
    }

    (*rootIndex)++;

    root->left = build(preorder, inorder, rootIndex, inorderLeft, mid);
    root->right = build(preorder, inorder, rootIndex, mid + 1, inorderRight);

    return root;
}

struct TreeNode *buildTree(int *preorder, int preorderSize, int *inorder, int inorderSize)
{
    int rootIndex = 0;
    return build(preorder, inorder, &rootIndex, 0, inorderSize);
}