LeetCode 957: Prison Cells After N Days
A clear explanation of simulating prison cell transitions efficiently using cycle detection.
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A clear explanation of simulating prison cell transitions efficiently using cycle detection.
A clear explanation of the Backspace String Compare problem using stack simulation and an O(1) space two-pointer scan.
A clear explanation of the Magic Squares In Grid problem using fixed-size subgrid validation.
A clear explanation of the Find And Replace in String problem using simultaneous replacement, source matching, and a replacement map.
A clear explanation of the Flipping an Image problem using row reversal, bit inversion, and an in-place two-pointer method.
A clear explanation of the Masking Personal Information problem using string parsing and format-specific masking rules.
A clear explanation of designing an iterator over a run-length encoded sequence without expanding it.
A clear explanation of generating grid coordinates in an outward clockwise spiral using simulation.
A clear explanation of computing the projection areas of stacked cubes from top, front, and side views.
A clear explanation of Design Circular Queue using a fixed array, a front pointer, and a size counter.
A clear explanation of counting how many pawns a rook can capture by scanning four directions on a chessboard.
A clear explanation of adding an integer to an array-form number using digit-by-digit simulation.
A clear explanation of maintaining the sum of even numbers after each array update.
A clear explanation of simulating robot movement on an infinite grid using direction vectors and obstacle lookup.
A clear explanation of transposing a matrix by swapping row and column indices.
A clear explanation of Lemonade Change using greedy simulation and bill counting.
A clear explanation of simulating an exam room by maintaining occupied seats in sorted order.
A clear explanation of solving Reveal Cards In Increasing Order using sorting and queue simulation over indices.
A clear explanation of solving Validate Stack Sequences by simulating stack push and pop operations.
A clear explanation of solving Valid Mountain Array by walking up the increasing slope and then down the decreasing slope.
A clear explanation of solving Unique Email Addresses using string normalization and a hash set.
A clear explanation of solving Minimize Malware Spread II by removing each infected node and simulating the final malware spread.
A string simulation solution for converting each word in a sentence into Goat Latin.
A simple simulation solution for counting how many 100-pixel lines are needed to write a string.
A clear explanation of simulating overflow in a champagne glass pyramid using dynamic programming.
A clear explanation of validating whether a Tic-Tac-Toe board can occur in a legal game.
A clear explanation of marking matching substrings and merging overlapping bold ranges.
A clear explanation of simulating water droplets over an elevation map by checking left first, then right.
A clear explanation of splitting a linked list into k consecutive parts with sizes as equal as possible.
A clear explanation of restoring a Candy Crush board to a stable state using repeated marking, crushing, and gravity simulation.
A clear explanation of removing line comments and block comments from source code using a state machine.
Simulate virus containment by repeatedly quarantining the most dangerous infected region and spreading the remaining regions.
Simulate asteroid collisions using a stack that keeps the surviving asteroids in order.
Check each number in a range by extracting its digits and testing whether every digit divides the original number.
Simulate falling squares on a number line and track the maximum stack height after each placement.
Simulate a baseball scoring system using a stack to process operations and compute the final score.
Find the next valid 24-hour time using only the digits from the current time.
A clear explanation of averaging neighboring pixels in a matrix using direct simulation.
A clear explanation of determining whether a robot returns to the origin after executing movement instructions.
A queue-based simulation for predicting which party wins after senators ban opponents in turn order.
A string parsing solution for reducing a linear equation into coefficient and constant terms.
A stack-based solution for computing exclusive execution time from nested start and end logs.
A clear explanation of Multiply Strings using grade-school multiplication with digit arrays.
A clear explanation of Squirrel Simulation using Manhattan distance and the special first trip.
A clear explanation of Reshape the Matrix using index mapping from the original matrix to the reshaped matrix.
A clear explanation of Student Attendance Record I using simple string checks and a one-pass counter solution.
A clear explanation of building the final tournament bracket by repeatedly pairing strongest and weakest teams.
A clear explanation of reversing the first k characters in every 2k block of a string.
A clear explanation of multiplying complex numbers represented as strings using algebraic expansion.
A clear explanation of returning matrix elements in diagonal zigzag order by grouping cells with the same row plus column index.
A clear explanation of calculating total poisoned duration by merging overlapping attack intervals.
A clear explanation of cleaning an unknown grid using DFS, relative coordinates, and physical backtracking.
A clear explanation of finding the longest streak of 1s in a binary array with a single pass.
A clear explanation of reformatting a license key by removing dashes, uppercasing characters, and grouping from the right.
A clear explanation of constructing the magical string by using the string itself as run-length instructions.
A clear explanation of validating IPv4 and IPv6 addresses by checking segment count, length, characters, range, and leading-zero rules.
A clear explanation of counting how many repeated copies of one string can be obtained as a subsequence of another repeated string.
A clear explanation of counting the perimeter of an island in a grid by adding land-cell edges and subtracting shared edges.
Count the number of word segments in a string by detecting transitions from spaces to non-space characters.
A clear explanation of checking whether rows and columns read the same using direct index comparison.
A clear explanation of fitting a sentence onto a screen using cyclic string simulation and greedy row transitions.
A clear explanation of adding two non-negative integer strings using manual digit-by-digit simulation.
A clear explanation of the Fizz Buzz problem using direct simulation and divisibility checks.
A clear explanation of validating a word abbreviation using two pointers and number parsing.
A clear explanation of finding the last remaining number after alternating left-to-right and right-to-left eliminations.
A clear explanation of Sparse Matrix Multiplication using non-zero entries to avoid wasted work.
A simple string scanning solution for generating every possible next state after flipping one consecutive ++ pair into --.
An in-place matrix simulation for computing the next state of Conway's Game of Life using temporary encoded states.
A clear explanation of the Add Digits problem using repeated digit sums first, then the digital root formula.
A clear explanation of finding all missing ranges inside an inclusive interval by scanning sorted unique numbers.
A clear explanation of implementing read with read4 when read may be called multiple times.
A clear explanation of implementing read using the given read4 API and copying only the needed characters.
A clear guide to formatting text with greedy line packing and even space distribution.
A clear guide to adding two binary strings using two pointers and a carry.
A clear guide to generating an n x n matrix filled from 1 to n squared in spiral order.
A clear guide to reading a matrix in spiral order using shrinking boundaries.
A clear explanation of generating the count-and-say sequence using run-length encoding.
A detailed explanation of parsing a string into a 32-bit signed integer with whitespace, sign, digit reading, and clamping rules.
A detailed explanation of converting a string into a zigzag pattern using row simulation.
Machines that simulate any other Turing machine, establishing the concept of programmable computation.