Tag LeetCode Easy

In this problem, we need to simulate the typing event with backspace.

In this problem, we need to utilize the DFS (Depth-First Search) approach to traverse the entire tree

Determine if a number is a power of three using a loop.

We can easily solve this problem with a loop or recursion. But is there another way? Definitely yes!

This problem can be seen as part of a series related to the "Contains Duplicate" problem, with a slight difference.

We can determine if one string is a subsequence of another string through a simple iteration.

'isomorphic' means each alphabet is map to another one. Discover how to solve this efficiently with iteration.