Generated by Codex with GPT-5

Quick facts

• Difficulty: MEDIUM
• Problem: Delete Node in a Linked List
• Main tags: Linked List

What the problem is really asking

This problem sounds impossible the first time it is heard.

In a normal singly linked list, deleting a node means changing the previous node’s next pointer so it skips the node being removed. But this problem does not give the head of the list or the previous node. It gives only the node that should disappear, and it guarantees that this node is not the tail.

Generated by Codex with GPT-5

Quick facts

• Difficulty: MEDIUM
• Problem: Pacific Atlantic Water Flow
• Main tags: Array, Depth-First Search, Breadth-First Search, Matrix

What the problem is really asking

Each cell in the grid is a height. Water can flow from a cell to one of its four neighbors if the neighbor is at the same height or lower.

Generated by Codex with GPT-5

Quick facts

• Difficulty: MEDIUM
• Problem: Target Sum
• Main tags: Array, Dynamic Programming, Backtracking
• Frequency in source list: 22.1

What the problem is really asking

Each number in nums must receive either a plus sign or a minus sign.

After choosing a sign for every element, the final expression must evaluate to target.

Generated by Codex with GPT-5

Quick facts

• Difficulty: MEDIUM
• Problem: Rotate List
• Main tags: Linked List, Two Pointers
• Frequency in source list: 25.6

What the problem is really asking

The input is a singly linked list and a non-negative integer k.

Rotating the list to the right by k means taking the last k nodes, preserving their order, and moving them to the front.

Generated by Codex with GPT-5

Quick facts

• Difficulty: MEDIUM
• Problem: String to Integer (atoi)
• Main tags: String

What the problem is really asking

The input is a string, and the task is to extract the integer prefix that follows a very specific parsing rule:

1. ignore leading spaces
2. read at most one optional + or -
3. read as many consecutive digits as possible
4. stop as soon as the next character is not a digit
5. clamp the result into the 32-bit signed integer range

So this is not a math problem. It is a parsing problem with a few edge cases that must be handled in the correct order.

Generated by Codex with GPT-5

Quick facts

• Difficulty: MEDIUM
• Problem: Subsets II
• Main tags: Array, Backtracking, Bit Manipulation

What the problem is really asking

This is the power set problem with one extra constraint that changes everything: the input can contain duplicate values, but the output cannot contain duplicate subsets.

If the array were all distinct, the job would be straightforward. At each position, either include the number or skip it, and every path through that decision tree would produce a unique subset.

Generated by Codex with GPT-5

Quick facts

• Difficulty: MEDIUM
• Problem: Sum of Subarray Minimums
• Main tags: Array, Dynamic Programming, Stack, Monotonic Stack
• Frequency in source list: 22.1

What the problem is really asking

For every contiguous subarray, take its minimum value. Then add all of those minimums together.

That sounds simple until the number of subarrays is considered. An array of length n has about n^2 / 2 subarrays, so listing each one and recomputing its minimum quickly becomes too slow.

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A Solar System That Is Not Typical

For a long time, astronomers treated the solar system as a reasonable template for how planets ought to be arranged: small rocky worlds close to the star, giant gas planets farther out. The exoplanet era has broken that assumption. After the discovery of hot Jupiters in the 1990s and the flood of Kepler data that followed, planetary science shifted from studying one familiar system to comparing thousands of strange ones. The article argues that this broader view has created a new field, exoplanet demographics, which looks for large-scale patterns in whole populations of planets instead of treating each world as an isolated curiosity.

Generated by Codex with GPT-5

What happened

Techmeme surfaced this April 16, 2026 story, and the original article is VentureBeat’s Salesforce launches Headless 360 to turn its entire platform into infrastructure for AI agents.

Salesforce is making a blunt strategic argument: in an agentic software world, the browser should stop being the main doorway into enterprise software. Headless 360 is its attempt to turn Salesforce from an application that humans click through into a programmable substrate that agents can operate directly. Instead of forcing every workflow through a web UI, the company now exposes platform capabilities as APIs, MCP tools, and CLI commands.

Generated by Codex with GPT-5

A Fuel Shock That Reorders Corporate Fortunes

The article argues that the Iran war’s oil shock is doing more than lifting headline inflation or making drivers angry at the pump. It is rapidly redrawing the map of corporate winners and losers. When oil rises from roughly \$60 a barrel to around \$100, and petrol moves from about \$3 a gallon to \$4, the effect is not evenly spread. Some businesses get an immediate windfall. Others are squeezed twice over: first by higher operating costs, then by consumers who have less money left for everything else.