std::experi..._permutation(3)

💖 NAME 💖

okay so welcome to the std::experi..._permutation(3) page from the C++ Standard Libary manual, bestie 💅✨

std::experimental::ranges::is_permutation — std::experimental::ranges::is_permutation

---

🌸 Synopsis 🌸

Defined in header <experimental/ranges/algorithm>, and here’s the whole declaration situation exactly as it is — we do not mess with code, periodt 💖

Defined in header <experimental/ranges/algorithm>
template< ForwardIterator I1, Sentinel<I1> S1, ForwardIterator I2,
Sentinel<I2> S2,

          class Pred = ranges::equal_to<>,
          class Proj1 = ranges::identity, class Proj2 =
ranges::identity >
(1) (ranges TS)
       requires IndirectlyComparable<I1, I2, Pred, Proj1, Proj2>
bool is_permutation( I1 first1, S1 last1, I2 first2, S2 last2, Pred
pred = Pred{},

                     Proj1 proj1 = Proj1{}, Proj2 proj2 = Proj2{}
);
template< ForwardRange R1, ForwardRange R2, class Pred =
ranges::equal_to<>,

          class Proj1 = ranges::identity, class Proj2 =
ranges::identity >
    requires IndirectlyComparable<ranges::iterator_t<R1>,
(2) (ranges TS)
ranges::iterator_t<R2>,
                                  Pred, Proj1, Proj2>
bool is_permutation( R1&& r1, R2&& r2, Pred pred = Pred{},

                     Proj1 proj1 = Proj1{}, Proj2 proj2 = Proj2{}
);
template< ForwardIterator I1, Sentinel<I1> S1, class I2,

          class Pred = ranges::equal_to<>,
          class Proj1 = ranges::identity, class Proj2 =
ranges::identity >
    requires ForwardIterator<std::decay_t<I2>> && !Range<I2> &&
(3) (ranges TS)
             IndirectlyComparable<I1, std::decay_t<I2>, Pred,
(3) (deprecated)
Proj1, Proj2>
bool is_permutation( I1 first1, S1 last1, I2&& first2_, Pred pred =
Pred{},

                     Proj1 proj1 = Proj1{}, Proj2 proj2 = Proj2{}
);
template< ForwardRange R1, class I2, class Pred =
ranges::equal_to<>,

          class Proj1 = ranges::identity, class Proj2 =
ranges::identity >
    requires ForwardIterator<std::decay_t<I2>> && !Range<I2> &&
(4) (ranges TS)
             IndirectlyComparable<ranges::iterator_t<R1>,
(4) (deprecated)
std::decay_t<I2>, Pred, Proj1, Proj2>
bool is_permutation( R1&& r1, I2&& first2_, Pred pred = Pred{},

                     Proj1 proj1 = Proj1{}, Proj2 proj2 = Proj2{}
);

1. Returns true if there exists a permutation of the elements in range [first1, last1) that makes the range equal to [first2, last2), and false otherwise. 💖
2. Same as (1), but uses r1 as the first source range and r2 as the second source range, as if using ranges::begin(r1) as first1, ranges::end(r1) as last1, ranges::begin(r2) as first2, and ranges::end(r2) as last2.
3. Same as (1), except that first2 is defined as if by std::decay_t<I2> first2 = std::forward<I2>(first2_); and last2 is first2 + (last1 - first1).
4. Same as (3), but uses r1 as the first source range, as if using ranges::begin(r1) as first1 and ranges::end(r1) as last1.

Two ranges are considered equal if they have the same number of elements and, for every iterator i in the range [first1, last1), ranges::invoke(pred, ranges::invoke(proj1, *i), ranges::invoke(proj2, *(first2 + (i - first1)))) is true.

🫶 Notwithstanding the declarations depicted above, the actual number and order of template parameters for algorithm declarations is unspecified. Thus, if explicit template arguments are used when calling an algorithm, the program is probably non-portable.

---

🌟 Parameters 🌟

• first1, last1 — the first range of the elements
• r1 — the first range of the elements
• first2, last2 — the second range of the elements
• r2 — the second range of the elements
• first2_ — the beginning of the second range of the elements
• pred — predicate to apply to the projected elements
• proj1 — projection to apply to the elements in the first range
• proj2 — projection to apply to the elements in the second range

---

🎀 Return value 🎀

true if the range [first1, last1) is a permutation of the range [first2, last2).

---

🔥 Complexity 🔥

At most O(N^2) applications of the predicate and each projection, or exactly N if the sequences are already equal, where N = last1 - first1.

However if SizedSentinel<S1, I1> && SizedSentinel<S2, I2> is satisfied and last1 - first1 != last2 - first2, no applications of the predicate and projections are made. ✨

---

😭 Example 😭

This section is incomplete

Reason: no example

---

🦋 See also 🦋

• is_permutation — determines if a sequence is a permutation of another sequence (C++11) (function template)
• next_permutation — generates the next greater lexicographic permutation of a range of elements (function template)
• prev_permutation — generates the next smaller lexicographic permutation of a range of elements (function template)

---

💀 Category 💀

• Todo no example

---

okay bye bestie — source/version http://cppreference.com, date 2024.06.10, and the footer title is std::experi..._permutation(3). mwah 💋🫶