When you begin to practice algorithms and data structures with LeetCode problems.

Remember to build your confidence and find the fun of algorihtms in your first step.

You should start with easy problems.

This is a list of categories with classic and easy problems for you.

## Array

Remove Duplicates from Sorted Array

Remove Duplicates from Sorted Array II

## String

First Unique Character in a String

## Tree

Binary Tree Preorder Traversal

Binary Tree Postorder Traversal

Binary Tree Level Order Traversal

## LinkedList

Intersection of Two Linked Lists

## DFS & BFS

## Backtracking

## Other references

How To Learn Data Structures And Algorithms is a roadmap for newbie.