1044. Longest Duplicate Substring
Given a string s, consider all duplicated substrings: (contiguous) substrings of s that occur 2 or more times. The occurrences may overlap.
Return any duplicated substring that has the longest possible length. If s does not have a duplicated substring, the answer is “”.
Given an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n.
A school is trying to take an annual photo of all the students. The students are asked to stand in a single file line in non-decreasing order by height. Let this ordering be represented by the integer array expected where expected[i] is the expected height of the ith student in line.
You are given an integer array heights representing the current order that the students are standing in. Each heights[i] is the height of the ith student in line (0-indexed).
Return the number of indices where heights[i] != expected[i].
Given a single-digit integer d and two integers low and high, return the number of times that d occurs as a digit in all integers in the inclusive range [low, right].
689. Maximum Sum of 3 Non-Overlapping Subarrays
Given an integer array nums and an integer k, find three non-overlapping subarrays of length k with maximum sum and return them.
Return the result as a list of indices representing the starting position of each interval (0-indexed). If there are multiple answers, return the lexicographically smallest one.
272. Closest Binary Search Tree Value II
Given the root of a binary search tree, a target value, and an integer k, return the k values in the BST that are closest to the target. You may return the answer in any order.
You are guaranteed to have only one unique set of k values in the BST that are closest to the target.
1931. Painting a Grid With Three Different Colors
You are given two integers m and n. Consider an m x n grid where each cell is initially white. You can paint each cell red, green, or blue. All cells must be painted.
Return the number of ways to color the grid with no two adjacent cells having the same color. Since the answer can be very large, return it modulo 109 + 7.
A password is considered strong if the below conditions are all met:
- It has at least 6 characters and at most 20 characters.
- It contains at least one lowercase letter, at least one uppercase letter, and at least one digit.
- It does not contain three repeating characters in a row (i.e., “…aaa…” is weak, but “…aa…a…” is strong, assuming other conditions are met).
Given a string password, return the minimum number of steps required to make password strong. if password is already strong, return 0.
In one step, you can:
- Insert one character to password,
- Delete one character from password, or
- Replace one character of password with another character.
1928. Minimum Cost to Reach Destination in Time
There is a country of n cities numbered from 0 to n - 1 where all the cities are connected by bi-directional roads. The roads are represented as a 2D integer array edges where edges[i] = [xi, yi, timei] denotes a road between cities xi and yi that takes timei minutes to travel. There may be multiple roads of differing travel times connecting the same two cities, but no road connects a city to itself.
Each time you pass through a city, you must pay a passing fee. This is represented as a 0-indexed integer array passingFees of length n where passingFees[j] is the amount of dollars you must pay when you pass through city j.
In the beginning, you are at city 0 and want to reach city n - 1 in maxTime minutes or less. The cost of your journey is the summation of passing fees for each city that you passed through at some moment of your journey (including the source and destination cities).
Given maxTime, edges, and passingFees, return the minimum cost to complete your journey, or -1 if you cannot complete it within maxTime minutes.
1434. Number of Ways to Wear Different Hats to Each Other
There are n people and 40 types of hats labeled from 1 to 40.
Given a 2D integer array hats, where hats[i] is a list of all hats preferred by the ith person.
Return the number of ways that the n people wear different hats to each other.
Since the answer may be too large, return it modulo 109 + 7.