Generated by Codex with GPT-5
HARDArray, String, Backtracking, Trie, MatrixThe input gives a letter grid and a list of candidate words. A word is valid if it can be traced through horizontally or vertically adjacent cells without reusing the same cell inside that one word.
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HARDArray, Sorting, Heap (Priority Queue), Simulation17.6This is not the classic “how many meeting rooms are needed?” question.
The number of rooms is fixed up front, and every meeting has to be assigned under three rules:
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HARDArray, Dynamic ProgrammingThis problem looks like a simulation question, but the hard part is not the simulation itself. The hard part is that every burst changes the future.
When balloon i is burst, the coins earned are:
Generated by Codex with GPT-5
HARDArray, Breadth-First Search, Heap (Priority Queue), Matrix17.6This is the 2D version of Trapping Rain Water.
Instead of one row of bars, there is a full grid of elevations. After rain falls, water can sit on low cells, but only if every path from that cell to the outer border is blocked by walls that are high enough.
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MEDIUMHash Table, Linked ListEach node in the list has two outgoing pointers:
next, which gives the usual linked-list orderrandom, which can point to any node in the list or to NoneThe task is to build a deep copy, not just another pointer to the same nodes.
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MEDIUMMath, Bit ManipulationTwo integers are given: dividend and divisor.
The task is to return the integer quotient of dividend / divisor, but with three constraints that make the problem interesting:
Generated by Codex with GPT-5
MEDIUMArray, Hash Table, MatrixThis problem is not asking to solve the Sudoku board.
It is only asking whether the current partially filled board is still legal. That means every filled digit must satisfy three rules at the same time:
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Moriba Jah’s article treats orbital debris not as a side effect of the space age but as the central environmental problem of modern spaceflight. The basic argument is simple: humanity has built an economy in orbit that behaves like a throwaway culture on Earth. Satellites and rocket parts are launched, used and abandoned, while the region around the planet grows more crowded with dead machinery and fragments from past collisions. What makes the situation alarming is not only the amount of debris already aloft but the speed at which the traffic is increasing. Jah notes that annual launches have exploded in just the past decade, and the number of trackable objects larger than 10 centimeters is already in the tens of thousands.
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Techmeme surfaced this April 19, 2026 story, and the direct article used here is The Verge’s Cloud development platform Vercel was hacked, which also points to Vercel’s official security bulletin.
Vercel says it identified unauthorized access to certain internal systems and has brought in incident-response specialists while notifying law enforcement. The company says its services remain operational and that, so far, it has identified only a limited subset of customers as affected. Those customers are being contacted directly.
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The article looks at the Iran war from the perspective of American oil and gas producers and argues that the industry’s apparent good fortune is real but fragile. At the CERAWeek conference in Houston, high oil prices and global anxiety created an atmosphere that bordered on celebration. If crude stays around \$100 a barrel, American producers stand to make a great deal of money. The article cites estimates of more than \$60bn in extra gains over a year, while liquefied-natural-gas exporters also benefit from the disruption of Qatari supply. In the narrowest short-term sense, the war is good business for the industry.
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