Leetcode Problem 1300-1399

1305. All Elements in Two Binary Search Trees 🌟🌟

Most intuitive Solution

• Traversal with any order and get all the nodes of the BST and then sort them.

By inorder traversal and merge sort

• We know that inorder traversal of BST gives us the sorted list.
• Then we can merge these two lists into one using merge technique similar to merge sort.

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1332. Remove Palindromic Subsequences 🌟

using reverse function

Checking if string is palindrome

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1337. The K Weakest Rows in a Matrix 🌟

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1365. How Many Numbers Are Smaller Than the Current Number 🌟

O(N^2) Time solution

• Brute force for each array element.

O(N) Time O(N) space optimization

• Store the count in a bucket and take the running sum.

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1379. Find a Corresponding Node of a Binary Tree in a Clone of That Tree 🌟🌟

DFS

• Simple dfs traversal.
• check if original node is null if yes then return null.
• if original node is equal to target node then return the cloned node.
• else recur ot left and right of the original and cloned subtrees and store the result in the left and right.
• if left is not null return left else return right.

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1389. Create Target Array in the Given Order 🌟

O(N^2) Time solution

• Brute force

O(N*logN) based on “smaller elements after self”.

• It is HARD level problem
• Will be added soon…

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1359. Count All Valid Pickup and Delivery Options 🌟🌟

DP Solution

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