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This problem gives us the root of a Binary Search Tree (BST) and an integer k. We must determine whether there are two distinct nodes in the tree whose values add up to k.

Each input line describes the full path of one file inside a file system. A path looks like: The disk name is the root and is not considered a folder. Every component between the disk and the file is a folder. The last component is always a file.

Each year the university sends a team of exactly n students to the finals. Some of those students may already have participated once before, and the rest are newcomers.

Aryo wants to choose a title for a new album from a list of candidate names. Some names have already been used in previous years. His decision rule has two layers. If a candidate name has never been used before, that is the best possible choice.

The problem gives an array called height, where each element represents the height of a vertical bar in an elevation map. Every bar has width 1. After rainfall, water may become trapped between taller bars. The task is to compute the total amount of water that can be trapped.

The problem gives an array of intervals where each interval is represented as [start, end]. Each interval describes a continuous range on a number line. The task is to remove the minimum number of intervals so that the remaining intervals no longer overlap.

We are given an undirected graph where cities are vertices and roads are edges. Each connected component of the graph is called a province. Vasya may additionally build tunnels between cities, but tunnels have two restrictions.

This problem asks us to count how many subsets of crimes satisfy two constraints simultaneously: 1. The total number of members used is at most n 2.

We are given two integers, k and l. The task is to determine whether l can be written as an exact power of k. In other words, we need to check whether there exists a non-negative integer n such that: $l = k^n$ If such an n exists, we print "YES" and also print the importance…

The problem describes a two-player game played on an array of stone piles. Each pile contains a positive number of stones, and the piles are arranged in a row. Alice and Bob alternate turns, with Alice always moving first.

We are given an $n times m$ table filled with consecutive integers starting from 1. The filling is done row by row, left to right.

The problem asks us to compute the maximum width among all levels of a binary tree. The important detail is that the width is not simply the number of non-null nodes at a level.

We need to validate whether a string follows the exact syntax of a Jabber ID.

This problem asks us to identify all sellers who did not make any sales during the year 2020. We are given three databas

The problem gives us a triangular array of integers and asks us to compute the minimum path sum from the top row to the bottom row. The input is a two-dimensional array called triangle, where: - The first row contains exactly one number.

The problem requires us to add one to a non-negative integer that is represented as a singly-linked list. Each node in the list contains a single digit, and the head of the list corresponds to the most significant digit.

The problem gives us several classes, where each class is represented as [passi, totali]. The value passi tells us how many students currently pass the exam, while totali tells us the total number of students in that class.

This problem asks us to generate monthly statistics for the year 2020 using information from three database tables: Driv

We are asked to determine whether a given number is almost lucky. A number is almost lucky if it is divisible by at least one lucky number. Lucky numbers are positive integers composed entirely of the digits 4 and 7, like 4, 7, 44, 47, 74, and so on.

This problem asks us to build the lexicographically largest possible string by repeatedly choosing characters from the front of two given strings.

The problem asks us to randomly pick an integer point from a set of non-overlapping rectangles in 2D space. Each rectangle is defined by its bottom-left (ai, bi) and top-right (xi, yi) corners.

We start from the sorted permutation 1 2 3 ... n. Someone chooses exactly one contiguous segment and reverses it. We are given the final permutation and must determine whether it could have been produced by exactly one such reversal. The task is not to sort the array.

The problem asks us to count how many distinct phone numbers of length n can be generated by moving a chess knight across a numeric keypad. The keypad layout looks like this: A knight moves in an L-shape. From any current digit, it can jump only to specific other digits.

The problem asks us to find the smallest element that appears in every row of a given m x n matrix mat, where each row is sorted in strictly increasing order. In other words, we need an element that is common to all rows and is the minimum among all such elements.

We are asked to determine the maximum number of banana pieces Maria can produce from a birthday cake decorated with n non-overlapping circular banana pieces using exactly k straight-line cuts. Each circle has a center coordinate (x, y) and a radius r.

The problem asks us to determine whether the elements of a given array can be rearranged so that they form an arithmetic

The problem is asking us to identify a redundant edge in a graph that started as a tree. A tree is a connected graph with n nodes and exactly n-1 edges, meaning it has no cycles. The input graph has n nodes and n edges, so by definition, it contains exactly one cycle.

This problem asks us to process a sorted singly linked list and remove every value that appears more than once. The important distinction is that we are not keeping one copy of duplicated values. Instead, every node containing a duplicated value must be removed entirely.

This problem asks us to assign students to seats such that every student occupies exactly one seat and no two students share the same seat. Each student can move left or right on a number line, and every movement by one position costs exactly one move.

We have a single tram traveling along a line with n stops, starting empty at the first stop and ending empty at the last stop. At each stop, a certain number of passengers exit before any new passengers enter.

The problem gives us a string representing a mathematical expression containing non-negative integers, spaces, and the four operators +, -, , and /. Our task is to evaluate the expression and return the resulting integer value.

The problem is asking us to identify the minimum set of vertices in a directed acyclic graph (DAG) such that starting from any of these vertices, all other nodes in the graph are reachable.

Each person visiting the embassy must pass through three consecutive stages. The first stage has k1 identical windows, each service taking t1 time. The second stage has k2 windows with service time t2, and the third stage has k3 windows with service time t3.

The problem asks us to calculate the sum of divisors for numbers in a given integer array nums, but only for those numbe

We have a large circle, the plate, with radius R. Inside it there is another circle, the Golden Honduras, with radius r. The Honduras circle is tangent to the plate from the inside, so its center is exactly R - r units away from the plate center.

The problem gives us a database table named Queries. Each row represents the outcome of running a particular query against a database.

Here’s a complete, detailed technical solution guide for LeetCode 1478 following your requested format and requirements.

This problem asks us to reroot a binary tree at a given leaf node. Normally, a binary tree has a single root, and every node points downward to its children. In this problem, each node also contains a parent pointer, which allows traversal upward toward the root.

We are asked to tile a rectangular floor of size n × m using three types of parquet planks. The first type is a 1×2 horizontal plank, the second is a 2×1 vertical plank, and the third is a 2×2 square plank.

We are given a weighted tree rooted at hall 1, where Gerald starts. The treasure is hidden uniformly at random in one of the other halls. Gerald only discovers the treasure when he first enters the correct hall.

We are given two strings, a and b, of equal length up to one million characters. The task is to find indices i and j in a such that if we perform a specific transformation, we get b.

The problem asks us to design a miniature spreadsheet system similar to Microsoft Excel. The spreadsheet contains cells arranged in rows and columns, where rows are numbered starting from 1 and columns are labeled using uppercase letters such as A, B, C, and so on.

The problem asks us to compute the sum of two integers without using the arithmetic operators + and -. Instead of relying on normal arithmetic, we must use bit manipulation to simulate how addition works at the binary level. The input consists of two integers, a and b.

The problem gives us an integer array nums of length n + 1, where every value is guaranteed to be in the range [1, n]. Since there are n + 1 numbers but only n possible distinct values, at least one number must appear more than once. The task is to return that duplicate value.

We are given a rectangular grid where each cell is either empty or marked with . Every cell represents a point located at the center of that cell. We need to count how many right triangles can be formed such that:

The problem asks us to find a subsequence of a given integer array nums such that the sum of that subsequence is as close as possible to a given integer goal.

There are m + n + 1 distinct cards in total. Shrek initially knows his own m cards, Donkey knows his own n cards, and one card is hidden on the table. Nobody knows the hidden card directly. Players alternate turns, with Shrek moving first.

This problem gives us an array of unique strings called dict, where every string has the same length. We must determine whether there exists at least one pair of strings that differ by exactly one character at the same position.

This problem models a small social network with two database tables. The Friendship table stores friendship relationship

The problem asks us to design a data structure that manages a fixed pool of phone numbers. Initially, every number from 0 to maxNumbers - 1 is available. The directory must support three operations efficiently. The get() operation should assign and return an available number.

The problem gives two inputs: a pattern string and a space-separated string of words. We need to determine whether the sequence of words follows the same structure as the sequence of characters in the pattern.

We are given the maximum length of a single SMS message and one complete text consisting of sentences separated by spaces. A sentence always ends with one of ., ?, or !. Words contain only letters.

The problem asks for the total number of distinct substrings of a given string s. A substring is any contiguous sequence of characters from the string, including single-character substrings and the string itself.

The problem asks us to find every element in an integer array that appears more than ⌊ n/3 ⌋ times, where n is the length of the array. The floor notation means we round down to the nearest integer.

The problem asks us to count the number of valid teams of three soldiers from a line of n soldiers, where each soldier h

The problem gives us a 2D integer matrix called grid and an integer x. In one operation, we may either add x to a cell or subtract x from a cell. Our goal is to make every value in the grid equal using the minimum number of operations.

This problem asks us to determine which words from a given list can be constructed using the characters available in another string, chars. A word is considered good if every character it needs exists in chars in sufficient quantity.

The problem asks us to group the nodes of a binary tree by their vertical columns and return those groups from left to right.

We are given a set of wooden bars, each with a positive integer length. Vasya wants to build towers by stacking bars of the same length. Each tower must consist of bars that are identical in length, but different towers can have different lengths.

The problem gives us an initially zero-filled array of size length. We are also given a list of update operations, where each update has the form: This means we must add inc to every element in the inclusive range from startIdx to endIdx.

We have an n × m grid. Every cell must contain one of four corner-shaped pipe pieces. Each piece connects exactly two adjacent sides of the cell.

The problem is asking to find the maximum dot product of two non-empty subsequences of arrays nums1 and nums2 such that

The problem gives two strings, s and p, both containing only lowercase English letters. We need to find every starting index in s where a substring is an anagram of p.

The problem asks us to count how many permutations of numbers from 1 to n satisfy a specific condition: all prime numbers must appear at prime-numbered indices (1-indexed).

The problem gives us an array of non-negative integers called nums. We need to count how many index pairs (i, j) satisfy the following conditions: - i < j - nums[i] + rev(nums[j]) == nums[j] + rev(nums[i]) Here, rev(x) means reversing the digits of the integer.

The problem asks us to divide a chocolate bar into k + 1 consecutive pieces such that we maximize the minimum total sweetness among those pieces. Each element in the input array sweetness represents the sweetness of a single chunk.

The problem gives us a directed graph with n nodes labeled from 0 to n - 1. Every edge in the graph has a color, either red or blue.

The problem presents a matrix isWater of size m x n where each cell is either water (1) or land (0). We are asked to assign heights to every cell in a way that satisfies three rules. First, all heights must be non-negative integers. Second, water cells must have a height of 0.

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The problem asks us to find the length of the longest consecutive sequence path in a binary tree, where a consecutive sequence path is defined as a path in which the values increase by exactly one from parent to child.

The problem gives us a row of houses, where each house must be painted using exactly one of three colors: red, blue, or green. The input is provided as a two-dimensional array named costs, where costs[i][j] represents the cost of painting the i-th house with the j-th color.

In this problem, we are given an even number of people standing around a circle. Every person must participate in exactl

This problem is essentially a simulation of the Candy Crush game, where we need to repeatedly crush candies in a grid until the board reaches a stable state. The input is an m x n matrix of integers representing different types of candies, and 0 represents empty cells.

This problem asks us to multiply two complex numbers represented as strings and return the result in the same string format.

We are given an integer array nums and an integer target. The goal is to find every unique quadruplet of numbers in the array whose sum equals the target value. A quadruplet consists of four elements: where all four indices are distinct.

The problem gives us an array nums, where each element represents a balloon containing a number. When we burst a balloon at index i, we gain coins equal to: The important detail is that the neighbors of a balloon change dynamically as balloons are removed.

The problem asks us to construct a special integer sequence using numbers from 1 to n. The resulting sequence has length 2 n - 1 because: - The number 1 appears exactly once. - Every number from 2 to n appears exactly twice.

This problem asks whether it is possible to divide n people into exactly two groups such that no pair of people who dislike each other end up in the same group.

This problem gives us a string s and an integer k. We are allowed to repeatedly perform one operation: - Choose one of the first k characters of the string. - Remove that character from its current position. - Append it to the end of the string.

The problem describes a two-player game involving a single heap of stones. There are n stones initially on the table, and players alternate turns removing stones. On each turn, a player may remove either 1, 2, or 3 stones. The player who removes the final stone wins the game.

The problem asks us to determine how many triplets from a given integer array nums can form a valid triangle. In geometric terms, a triangle is valid if the sum of any two sides is greater than the third side.

We are asked to count the number of times a digital clock shows a moment where at least k digits change simultaneously while Vasya is watching it. The clock is not necessarily 24-hour or 60-minute - it has h hours and m minutes, where both are arbitrary integers up to 10^9.

The problem asks us to determine whether an integer array forms a perfect sequence of consecutive numbers without gaps o

The problem gives us a sorted list containing every integer from 1 to n. We repeatedly eliminate numbers in alternating directions until only one number remains.

The problem gives an integer array nums with n elements. In a single move, you are allowed to increment exactly n - 1 elements by 1. Your goal is to determine the minimum number of such moves required to make every element in the array equal.

The problem gives us an m x n binary matrix where each cell contains either 0 or 1. We must count how many rectangular submatrices consist entirely of ones. A submatrix is any contiguous rectangular region inside the matrix.

The problem gives us a database table named RequestAccepted, where each row represents a successfully accepted friend request between two users. Every record contains a requesterid, an accepterid, and the date the request was accepted.

We are given an undirected multigraph. Floors are vertices, staircases are edges. Harry starts at floor 1 and wants to visit every floor at least once. The graph is dynamic. Between Harry's walks, Ron and Hermione may modify staircases.

Five people stand in a queue in a fixed order: Sheldon, Leonard, Penny, Rajesh, Howard. Whenever the person at the front buys a cola, that person immediately creates a copy of themselves, and both copies go to the back of the queue. The queue keeps growing forever.

The problem gives us the root of a binary search tree, but exactly two nodes in the tree have had their values swapped accidentally. Our task is to restore the tree so that it once again satisfies the binary search tree property, without modifying the tree structure itself.

The problem gives us a string consisting only of digits, and asks us to split it into a sequence of integers that behaves like a Fibonacci sequence. A Fibonacci-like sequence follows three important rules: 1.

The problem asks us to determine the minimum number of operations required to transform a given password into a "strong" password according to three rules. A strong password must satisfy all of the following conditions: 1.

We are given four stick lengths, and we must choose exactly three of them. Depending on the relationship between those three lengths, there are three possible outcomes.

This problem gives us a two dimensional grid where each cell contains either 'X' or '.'. An 'X' represents part of a battleship, while '.' represents empty water. The important rule is that battleships are always placed in straight lines.

We are given the results of an entire Formula One season. Each race lists drivers from first place to last place. The championship winner depends on one of two ranking systems.

This problem asks us to find the names of all salespeople who have never handled an order for the company named "RED". We are given three database tables: - SalesPerson contains information about each salesperson, including their unique salesid and name.

This problem simulates a lemonade stand where each lemonade costs 5, 20 bill. The challenge is to provide exact change to every customer as they pay. The input is a list of integers bills, where each element represents the bill a customer gives.

We have an undirected graph where each vertex stores some positive integer, the number of mushrooms on that lawn. For every known edge, we are given two values: the gcd of the two endpoint values and the lcm of the two endpoint values.

We are asked to find the longest contiguous substring of a string s that avoids certain "boring" substrings. In other words, given a string s and a small list of forbidden patterns b1, b2, ...

The problem asks us to perform a level order traversal of an n-ary tree. In other words, we need to return the values of the tree nodes grouped by their depth. The root node represents level 0, its immediate children are level 1, their children are level 2, and so on.