摘要：A matrix diagonal is a diagonal line of cells starting from some cell in either the topmost row or leftmost column and going in the bottom-right direc 阅读全文

摘要：Given a palindromic string of lowercase English letters palindrome, replace exactly one character with any lowercase English letter so that the result 阅读全文

摘要：There is a one-dimensional garden on the x-axis. The garden starts at the point 0 and ends at the point n. (i.e The length of the garden is n). There 阅读全文

摘要：Given a binary tree root and an integer target, delete all the leaf nodes with value target. Note that once you delete a leaf node with value target,  阅读全文