How to Find Words That Can Be Formed by Characters?
You are given an array of strings words and a string chars. A string is good if it can be formed by characters from chars (each character can only …
Author: ACMer
How to Compute the Maximum Difference Between Node and Ancestor?
Given the root of a binary tree, find the maximum value V for which there exists different nodes A and B where V = |A.val – B.val| and A …
How to Compute the Day of the Year?
Given a string date representing a Gregorian calendar date formatted as YYYY-MM-DD, return the day number of the year. Example 1: Input: date = “2019-01-09” Output: 9 Explanation: Given …
4Sum – Find Unique Quadruplets that Sum to Target using O(N^3) Four Pointers Algorithm
Given an array nums of n integers and an integer target, are there elements a, b, c, and d in nums such that a + b + c + …
The Subsequence Algorithm for Two Strings – How to Check if a String is Subsequence of Another?
Given a string s and a string t, check if s is subsequence of t. You may assume that there is only lower case English letters in both s …