Description https://leetcode.com/problems/find-and-replace-in-string/ To some string S, we will perform some replacement operations that replace groups of letters with new ones (not necessarily the…

Description https://leetcode.com/problems/jewels-and-stones/ You’re given strings J representing the types of stones that are jewels, and S representing the stones you have.  Each character in S is…

Description https://leetcode.com/problems/cracking-the-safe/ There is a box protected by a password. The password is a sequence of n digits where each digit can be…

Description https://leetcode.com/problems/expressive-words/ Sometimes people repeat letters to represent extra feeling, such as “hello” -> “heeellooo”, “hi” -> “hiiii”.  In these…

Description https://leetcode.com/problems/isomorphic-strings/ Given two strings s and t, determine if they are isomorphic. Two strings are isomorphic if the characters in s can be replaced…

Description https://leetcode.com/problems/strobogrammatic-number/ A strobogrammatic number is a number that looks the same when rotated 180 degrees (looked at upside down).…

Description https://leetcode.com/problems/most-common-word/ You are playing the Bulls and Cows game with your friend. You write down a secret number and ask your…

Description https://leetcode.com/problems/most-common-word/ Given a paragraph and a list of banned words, return the most frequent word that is not in the…

Description https://leetcode.com/problems/next-closest-time/ Given a time represented in the format “HH:MM”, form the next closest time by reusing the current digits.…

Description https://leetcode.com/problems/longest-substring-with-at-most-two-distinct-characters/ Given a string s , find the length of the longest substring t  that contains at most 2 distinct characters. Example 1: Input: “eceba”…