leetcode
link: Shortest Bridge Thought Since the question ask for shortest, so BFS probabely the best algorithms to solve it. But notice, I will use 2 bfs funciton, one to find the edge of first island, the other one is to reach another island based on first edge. BFS1: input: start
leetcode
Link 931.Minimum Falling Path Sum Thought DFS When first seeing this question, DFS prompt into my mind directly. Take Any node from first level as start, and search down stream. Until reach node in last level. For any path, it will have a value. Find the minimum value and
leetcode
Link: Unique Email Addresses Thought Brutal Force Solution This question is pretty simple (and it actually is an esay one). A naive approache is, split the name and domain. For the name, remove every thing after first '+', and then replace all '.' as empty. For the domain,