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tags. The deque class in Python can function as both a stack and a queue. 19 solved questions so far. LeetCode 337. Also keep a counter for fresh oranges! BFS is the most commonly used approach. Even if we needed the matrix later one could always restore the original value after the dfs call. So I've been trying to solve LeetCode 417.Pacific Atlantic Water Flow for almost 5 hours this afternoon, and I'm now very exhausted and frustrated cuz I really have no idea why my code doesn't work.. My DFS soluton passed LeetCode OJ (thank God) but unfortunately my two attempts to solve the problem with BFS all failed.. First of, a tree can be thought of as a connected acyclic graph with N nodes and N-1 edges. leet code questions (1) leetcode (26) Leetcode 1-10 (1) leetcode 1-251 questions with web links (1) Leetcode 10 (1) Leetcode 10: Regular expression matching (23) Leetcode 102: Binary tree level order traversal (4) Leetcode 103: Binary Tree Zigzag Level Order traversal (2) Leetcode 109: Convert sorted list to binary search tree (3) A graph is bipartite graph if and only if it is 2-colorable. Since free questions may be even mistakenly taken down by some companies, only solutions will be post on now. There are many leetcode hard that can simply never be asked in an hour-long interview. Before I give the code there are two things that I will be using in the next posts about BFS questions, they’ll be used again and again: [(1,0), (-1,0), (0,1), (0,-1)] represent the four directions. I broke this post into 2 parts as it got too long, I will visit BFS in the next part. The Hamming distance between two integers is the number of positions at which the corresponding bits are different.Given two integers x and y, calculate the Hamming distance.. Very short passage where we see how even when we move, God moves with us. For those of you who have done a lot of questions on Leetcode (and CTCI, EPI, etc) how many questions (and of which difficulty) did it take you until you were able to easily pass the majority of your Big-N-esque interviews? Word ladder II is great for reviewing: 1. BFS stands for Breadth First Search is a vertex based technique for finding a shortest path in graph. In almost all such cases the way to is BFS. The Shortest path is: 2 -> 1, which is of length 2 Input . DFS is all about diving as deep as possible before coming back to take a dive again. Example. Explanation. Why queue? BSF Study Questions Genesis: Lesson 18, Day 3: Genesis 28:10-11. My blog for LeetCode Questions and Answers... leetcode Question: Perfect Squares ... 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