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They say that the time complexity for the following code is O(n^2). But in my opinion it should be O(nlogn). I'm confident about calculating O() for most algorithms, but here there's a divide and conquer algorithm, which runs as T(n) = T(n/2) + O(n), which in my opinion should be working in O(nlogn) by the master method?

They say that the time complexity for the following code is O(n^2). But in my opinion it should be O(nlogn). I'm confident about calculating O() for most algorithms, but here there's a divide and conquer algorithm, which runs as T(n) = T(n/2) + O(n), which I believe should be working in O(nlogn) by the master method?

An algorithm is given on GeeksForGeeks.com for constructing a Binary Search Tree from its preorder traversal. They say that the time complexity for the following code is O(n^2). But in my opinion it should be O(nlogn). Can someone please tell how the complexity is O(n^2)?

The first element of preorder traversal is always root. We first construct the root. Then we find the index of first element which is greater than root. Let the index be ‘i’. The values between root and ‘i’ will be part of left subtree, and the values between ‘i+1′ and ‘n-1′ will be part of right subtree. Divide given pre[] at index “i” and recur for left and right sub-trees. For example in {10, 5, 1, 7, 40, 50}, 10 is the first element, so we make it root. Now we look for the first element greater than 10, we find 40.

An algorithm is given on GeeksForGeeks.com for constructing a Binary Search Tree from its preorder traversal.

They say that the time complexity for the following code is O(n^2). But in my opinion it should be O(nlogn). I'm confident about calculating O() for most algorithms, but here there's a divide and conquer algorithm, which runs as T(n) = T(n/2) + O(n), which in my opinion should be working in O(nlogn) by the master method?

Can someone please tell how the complexity is O(n^2)?

The first element of preorder traversal is always root. We first construct the root. Then we find the index of first element which is greater than root. Let the index be ‘i’. The values between root and ‘i’ will be part of left subtree, and the values between ‘i+1′ and ‘n-1′ will be part of right subtree. Divide given pre[] at index “i” and recur for left and right sub-trees.

For example in {10, 5, 1, 7, 40, 50}, 10 is the first element, so we make it root. Now we look for the first element greater than 10, we find 40.

An algorithm is given on GeeksForGeeks.com for constructing a Binary Search Tree from its preorder traversal. They say that the time complexity for the following code is O(n^2). But in my opinion it should be O(nlogn). Can someone please explain the complexity?

An algorithm is given on GeeksForGeeks.com for constructing a Binary Search Tree from its preorder traversal. They say that the time complexity for the following code is O(n^2). But in my opinion it should be O(nlogn). Can someone please tell how the complexity is O(n^2)?