Data Structures

Short String Optimization

Difficulty

Asked at IMC Trading

Theory: Data Structures You Implement, Not Import

Read the problem, hints and solution here. The editor needs a bigger screen: open this page on a laptop to write and run your code.

xxxxxx xxxxx xxxxxx xx x xxxxxxx xxxxxx xx xxxxx. xxxxxxx, xxxxx xxx, xxxxx xxxxx, xxxxxxx xxxxx: xxxxx xxxxxx xxxxxxxxxx, xxxxxxx xxx xxxxxxxxx xxxxxxxx xx xxxxx x xxx. x xxxxxx xxxx xxxxxxx xxx xxxx xxx "xxxx" xxxx xx xxxxxxxxx xxxx, x xxxx, xxx x xxxxx xxxx xx xxx xxx xxxx, xxx xxxx xxxxx xxxx xxxxx xxxx xxxxxx xx xxx xxxxxx xx xxx xxxxxxx xxxxxxxx.

xx xxx::xxxxxx xxxx xxx. xx xx xxxx xxxxxxxxx xxx xxxxxxxxxx xxxx xxxxxx xxx xxxxxx xxxxxx, xxx xxxxx xxxxxxxxxxxxxx xxx xxxx xxxx xxxx xxxx.

xxxxxxxxx xxxxxxxxx xxxx xx xxxxxx xxxxxxxx xx xx.

xxxxxxxxx(xxxx), xxxxxx(xxxx)
xxxx(), xxxxxxxx(), x_xxx(), xxxx()
xx_xxxxx() — xxxx xxxxx xxx xxxxxxxxxx xxxx xxxxxx xxx xxxxxx

xxx xxxxxx xx xxxxxx xxxx-xxxxxxxxxx, xx x_xxx() xx xxxxx xx xxx xxxx. xxxx xx xxx xxxxxxx xx xxxxx xx xxx xxxx, xxx xxxxxx xxxxxxx xxxx xxx xxxxx xxxx xxxxxxxx, xxxxx xxxx xx xx xxxxx xxx xxxx xxxxx xxxxxx.

xxx xxxxxx xxxxxxxx xxx xx xxxxxxxxxxxx, xx xxxxx xxxxxxx xxxxx xxx xxxx xx xxxxxxxx xxxxxx xxxx xxxxxxx.

xxxxxxxx

xxxxxxxxx x("xxxx");                       // x xxxxxxxxxxx, xx_xxxxx()
xxxxxxxxx xxxxx("xxxxxxxxxxxxxxxxxxxxxx"); // xx xxxxx: x xxxxxxxxxxx
xxxxxxxxx xxxx("xxxxxxxxxxxxxxxxxxxxxxx"); // xx xxxxx: x xxxxxxxxxx

xx xx xxxx++'x xxxxxxxxx xxx x xx-xxxx xxxxxx. xxxxxxx++ xxxxx xx xxxx x xxxxxxxxx xxxxxx xxx xx xxxxx xxxxx. xxxx xxx xxxxxxxxxx, xxx xxx xxxxxxxxxx xx xxx x xxxxxxx'x xxxxxxxxxx xxxxxxx xxx xxxxxx xxxx xxx xxxxxx xxxxxxxx xxxxxxx.

xxxxxxxxxxx

xxxxx xxx xxxxxxxxxx xxxx xxxx xx xxxxxxx xx xxx xxxxx. xxxxxxxxxxx xxxx xxxxxx xx xxx x xxxxxx xxxx xx xxxxxxxxx xxxx xxx xxxxxx xxxxxx xxxxx xx xxx xxxxxxx, xxx xxx xxxxxx xxxxx xxxxxx xxxxxx xxx xxxxxxxxxx.
xx xxxxxx xxxx xxxxxx xxxx xxxxxxxx xxxx xxx xxxxxxx xxxxx xxx xxxx xxx xxx xxxxxxxxxx xxxxx xx.
xxxxxx xx xxxxxxxxxxxxx, xxx xxx xxxxxx xxxxx xxxxxx xxx xxxxxxxxx xxxxxxxxxx: xxx xxxxx xxxx xxxxxxxx xx xxx xx-xxxx xxxxxx xxxxxxxx xxxxxxx, xx xxx xxxx xxxxx xxxxxx xx xxxx xx xxxxxx (xx xx xxxxxxxxxx xxxx xx x xxxxxxxx-xx xxxxxx), xxx xxxxx xxxxx xxxxxx xxxxxxx xxx xxxxxxx xxxxxxxx, xxxxx xxxxxx xxx xxxx xxxxx xxxxxx xx x xxxxxx xxxxxx xxxxx xxxx.
x xxxxxxx-xxxxxxxxxxx xxxxxx xx xxxxx, xxxx-xxxxxxxxxx, xxx xxxxxxxxx xxxxxxx.
xxxx xxx xxxxxxxxxx xxx xxxxxxx. xxxx xx xxx xxxxxxx xxxxxxxxx, xxx x xxxx xxxxxx.

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Language: C++SsoString

#include <cstddef>
#include <cstdlib>
#include <cstring>
#include <new>
#include <string_view>

// ...
// ...
// ...
// ...
namespace probe {
inline long long& counter() {
    static long long calls = 0;
    return calls;
}
inline long long allocations() { return counter(); }
inline void reset() { counter() = 0; }
}  // ...

void* operator new(std::size_t bytes) {
    ++probe::counter();
    void* p = std::malloc(bytes ? bytes : 1);
    if (!p) throw std::bad_alloc();
    return p;
}
void* operator new[](std::size_t bytes) { return ::operator new(bytes); }
void operator delete(void* p) noexcept { std::free(p); }
void operator delete[](void* p) noexcept { std::free(p); }
void operator delete(void* p, std::size_t) noexcept { std::free(p); }
void operator delete[](void* p, std::size_t) noexcept { std::free(p); }

// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
// ...
class SsoString {
public:
    static constexpr std::size_t kInline = 22;

    SsoString() { /* ... */ }

    explicit SsoString(std::string_view text) {
        // ...
        (void)text;
    }

    ~SsoString() {
        // ...
    }

    SsoString(const SsoString&) = delete;
    SsoString& operator=(const SsoString&) = delete;

    void append(std::string_view text) {
        // ...
        (void)text;
    }

    std::size_t size() const { return size_; }

    std::size_t capacity() const {
        // ...
        return 0;
    }

    bool is_small() const {
        // ...
        return true;
    }

    const char* c_str() const {
        // ...
        return small_;
    }

    std::string_view view() const { return std::string_view(c_str(), size_); }

private:
    char small_[kInline + 1] = {};
    char* heap_ = nullptr;
    std::size_t size_ = 0;
    std::size_t heap_capacity_ = 0;
};

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