Data Structures

LRU Cache With Expiry

Difficulty

Asked at DRW

Theory: Data Structures You Implement, Not Import

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Available in Python and C++. You are solving it in C++. Switch to Python

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Language:

Python 3.12 C++23

run_ops

#include <cstddef>
#include <optional>
#include <string_view>
#include <vector>

class TTLCache {
public:
    // ...
    // ...
    explicit TTLCache(std::size_t capacity) {
        // ...
        (void)capacity;
    }

    // ...
    // ...
    // ...
    long long get(long long key, long long now) {
        // ...
        (void)key;
        (void)now;
        return -2;
    }

    // ...
    // ...
    // ...
    // ...
    void put(long long key, long long value, long long ttl, long long now) {
        // ...
        (void)key;
        (void)value;
        (void)ttl;
        (void)now;
    }
};

// ...
// ...
struct Op {
    std::string_view kind;
    long long now = 0;
    long long key = 0;
    long long value = 0;
    long long ttl = 0;
};

// ...
// ...
std::vector<std::optional<long long>> run_ops(std::size_t capacity, const std::vector<Op>& ops) {
    TTLCache cache(capacity);
    std::vector<std::optional<long long>> out;
    out.reserve(ops.size());
    for (const Op& op : ops) {
        if (op.kind == "get") {
            out.emplace_back(cache.get(op.key, op.now));
        } else {
            cache.put(op.key, op.value, op.ttl, op.now);
            out.push_back(std::nullopt);
        }
    }
    return out;
}

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