• Difficulty - Medium
    Total Plays - 16
    Allowed Time - 10 sec
    Best time - 3.454

    What does delete do to a mapping entry?

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    #A
    #B
    #C
    #D
    Explanation:
    Deleting a mapping key resets its value to the default type value. The key itself still exists conceptually since mappings do not track keys.
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  • Difficulty - Medium
    Total Plays - 16
    Allowed Time - 10 sec
    Best time - 1.444

    Which data location persists across transactions?

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    #A
    #B
    #C
    #D
    Explanation:
    Storage persists on-chain across transactions and blocks. Memory and calldata are temporary and cleared after execution completes.
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    J

    Technical Support Engineer

    Jito Labs • Full Time • NA

    United States (Remote) Posted: Dec 29, 2025
    Job description
    Jito Labs builds high-performance distributed systems on Solana, including the Jito-Solana client and block-building infrastructure used by validators and MEV participants. The team operates as a small, profitable engineering-focused company working on production-grade blockchain infrastructure. As a Technical Support Engineer, you will act as a technical point of contact for...
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  • Job Expired
    P

    Research Engineer

    Plasma • Full Time • NA

    London, United Kingdom (On-site) Posted: Dec 29, 2025
    Job description
    Plasma is building a purpose-designed blockchain optimized for stablecoin payments, focusing on performance, predictability, and security for real-world financial use cases. The network is fully EVM-compatible, uses Reth as its execution layer, and runs on a custom high-performance consensus protocol, PlasmaBFT. As a Research Engineer, you will work within a...
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  • Job Expired
    P

    Fullstack Engineer

    Paradex • Full Time • NA

    Singapore (On-site) Posted: Dec 29, 2025
    Job description
    Paradex is a decentralized finance platform building a unified system that combines exchange trading, asset management, and borrow/lend functionality on a high-performance blockchain. The team operates with a flat structure and focuses on shipping production-grade systems without traditional management layers. As a Fullstack Engineer, you will own the end-to-end development...
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  • Job Expired
    P

    Data Engineer

    Paradex • Full Time • NA

    Remote Posted: Dec 29, 2025
    Job description
    Paradex is a decentralized finance platform combining exchange trading, asset management, and borrow/lend functionality within a single unified account structure. The company operates a high-throughput blockchain-based system supporting a wide range of spot and derivatives markets. As a Data Engineer, you will be responsible for designing and maintaining the data...
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  • Difficulty - Medium
    Total Plays - 15
    Allowed Time - 10 sec
    Best time - 4.491

    What happens if a public variable name conflicts with a function name?

    Tip: Click "Play" to reveal options and start playing.

    #A
    #B
    #C
    #D
    Explanation:
    Public variables automatically generate getter functions. If a function shares the same name, the compiler prioritizes the variable-generated getter, shadowing the function definition.
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  • Difficulty - Medium
    Total Plays - 15
    Allowed Time - 10 sec
    Best time - 3.590

    Which keyword prevents further inheritance of a contract?

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    #A
    #B
    #C
    #D
    Explanation:
    Solidity does not support a final or sealed keyword for contracts. Any contract can be inherited unless architectural constraints are enforced manually.
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  • Difficulty - Medium
    Total Plays - 13
    Allowed Time - 10 sec
    Best time - 3.845

    Which function type cannot access msg.sender?

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    #A
    #B
    #C
    #D
    Explanation:
    pure functions cannot read blockchain context such as msg.sender or block.timestamp. They are restricted to computation based solely on input parameters and local variables
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  • Difficulty - Medium
    Total Plays - 8
    Allowed Time - 10 sec
    Best time - 3.516

    What breaks if virtual is omitted in multiple inheritance?

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    #A
    #B
    #C
    #D
    Explanation:
    Without the virtual keyword, a function cannot be overridden in derived contracts. This breaks the override chain and prevents proper polymorphic behavior in multiple inheritance scenarios.
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  • Difficulty - Medium
    Total Plays - 5
    Allowed Time - 10 sec
    Best time - 10

    Which Solidity construct enforces compile-time immutability?

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    #A
    #B
    #C
    #D
    Explanation:
    constant variables are evaluated at compile time and embedded directly into contract bytecode. This guarantees immutability and avoids any runtime storage access or gas cost.
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  • Difficulty - Medium
    Total Plays - 4
    Allowed Time - 10 sec
    Best time - 10

    What default value does an uninitialized storage pointer hold?

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    #A
    #B
    #C
    #D
    Explanation:
    An uninitialized storage pointer defaults to storage slot zero. This can overwrite critical state variables such as ownership or balances, making it a high-severity audit issue.
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