Generated by Codex with GPT-5
MEDIUMArray, Dynamic Programming, MatrixThe input is a grid of "0" and "1" values. The job is to find the area of the largest square made entirely of 1s.
The part that usually traps people is the word “square.” A brute-force approach tends to ask:
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MEDIUMArray, Breadth-First Search, MatrixThe grid has three kinds of cells: empty (0), fresh oranges (1), and rotten oranges (2). Every minute, any fresh orange touching a rotten orange in the four main directions also becomes rotten.
Generated by Codex with GPT-5
HARDArray, Binary Search, Dynamic Programming, Greedy, Prefix SumThe input array must be cut into exactly k non-empty, contiguous pieces. Each cut creates one subarray, and the score of a split is the largest subarray sum that appears anywhere in that split.
Generated by Codex with GPT-5
MEDIUMArray, Binary SearchThe array is sorted, and every value appears exactly twice except for one value that appears once.
If the array were not sorted, the quickest idea would be XOR: identical values
cancel out, so the final XOR is the answer. That works in O(n) time and
O(1) space.
Generated by Codex with GPT-5.4
Difficulty: MEDIUM
Problem: Sort an Array
The task is deliberately simple to state: given an integer array, return the same values in ascending order. The interview signal is not whether someone knows Python’s built-in sort, but whether they can implement a sorting strategy with clear time and space guarantees.
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HARDArray, Dynamic Programming, Stack, Matrix, Monotonic StackThe matrix contains only "0" and "1", and the goal is to find the area of
the largest axis-aligned rectangle made entirely of "1" cells.
Generated by Codex with GPT-5.4
MEDIUMArray, Math, Two PointersThe problem gives an array nums and an integer k. The task is to rotate the
array to the right by k positions, modifying the original list in place.
Generated by Codex with GPT-5
MEDIUMDepth-First Search, Breadth-First Search, Graph Theory, Topological SortThere are numCourses courses labeled from 0 to numCourses - 1.
Each prerequisite pair [a, b] means course b must be finished before course a.
Generated by Codex with GPT-5
MEDIUMArray, Backtracking, Bit ManipulationGiven an array nums of distinct integers, return every possible subset of those numbers.
A subset can contain none of the numbers, some of the numbers, or all of the numbers. The empty subset [] is valid, and the full array is valid too. Because the input numbers are distinct, there is no duplicate-handling problem in the base version.
Generated by Codex with GPT-5
HARDArray, Stack, Monotonic StackEach bar in the histogram has width 1, and the goal is to find the largest
possible rectangle that can be formed by taking one or more adjacent bars.