953. Verifying an Alien Dictionary
In an alien language, surprisingly they also use english lowercase letters, but possibly in a differ...
944. Delete Columns to Make Sorted
We are given an array A of N lowercase letter strings, all of the same length. Now, we may choose an...
942. DI String Match
Given a string S that only contains "I" (increase) or "D" (decrease), let N = S....
941. Valid Mountain Array
Given an array of integers arr, return true if and only if it is a valid mountain array. Recall that...
938. Range Sum of BST
Given the root node of a binary search tree, return the sum of values of all nodes with a value in t...
937. Reorder Data in Log Files
You have an array of logs. Each log is a space delimited string of words. For each log, the first wo...
933. Number of Recent Calls
You have a RecentCounter class which counts the number of recent requests within a certain time fram...
929. Unique Email Addresses
Every email consists of a local name and a domain name, separated by the @ sign. For example, in ali...
893. Groups of Special-Equivalent Strings
You are given an array A of strings. A move onto S consists of swapping any two even indexed charact...
Long Pressed Name
Your friend is typing his name into a keyboard. Sometimes, when typing a character c, the key might ...