Problem: 1391. Check if There is a Valid Path in a Grid Level: Medium Check whether there is a valid path from the top-left cell to the bottom-right cell. Each grid cell has a street type, and you can only move to a neighboring cell if both streets connect to each other. Solution: - Use BFS starting from (0, 0). - For each street type, store the two directions it can move. - When moving to a neighbor, check whether the neighbor has a direction that connects back to the current cell. - If yes, push it into the queue and mark it as visited. At the end, return whether (n - 1, m - 1) was visited. Source Code: https://ide.usaco.guide/OrD--qQIDGM3QrchS0q

Problem: 2452. Words Within Two Edits of Dictionary Level: Medium Find all query words that differ from at least one dictionary word in at most two character positions, and return them in their original order. Solution: - A transformation is valid if the Hamming distance between a query word and a dictionary word is ≤ 2. - For each query, iterate through all dictionary words and compute the character-wise mismatch count. - If any dictionary word has ≤ 2 mismatches, include the query in the result and stop further checks for that query (aka. early break). Source Code: https://ide.usaco.guide/OqpSkK6fA48u0WTGvdO

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