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      std::ranges::make_heap

      From cppreference.com
      <cpp‎ |algorithm‎ |ranges
       
       
      Algorithm library
      Constrained algorithms and algorithms on ranges(C++20)
      Constrained algorithms, e.g.ranges::copy,ranges::sort, ...
      Execution policies(C++17)
      Sorting and related operations
      Partitioning operations
      Sorting operations
      Binary search operations
      (on partitioned ranges)
      Set operations (on sorted ranges)
      Merge operations (on sorted ranges)
      Heap operations
      Minimum/maximum operations
      (C++11)
      (C++17)
      Lexicographical comparison operations
      Permutation operations
      C library
      Numeric operations
      Operations on uninitialized memory
       
      Constrained algorithms
      All names in this menu belong to namespacestd::ranges
      Non-modifying sequence operations
      Modifying sequence operations
      Partitioning operations
      Sorting operations
      Binary search operations (on sorted ranges)
             
             
      Set operations (on sorted ranges)
      Heap operations
      make_heap
               
      Minimum/maximum operations
      Permutation operations
      Fold operations
      Operations on uninitialized storage
      Return types
       
      Defined in header<algorithm>
      Call signature
      template<std::random_access_iterator I,std::sentinel_for<I> S,

               class Comp=ranges::less,class Proj=std::identity>
          requiresstd::sortable<I, Comp, Proj>

      constexpr I make_heap( I first, S last, Comp comp={}, Proj proj={});
      (1)(since C++20)
      template<ranges::random_access_range R,

               class Comp=ranges::less,class Proj=std::identity>
          requiresstd::sortable<ranges::iterator_t<R>, Comp, Proj>
      constexprranges::borrowed_iterator_t<R>

          make_heap( R&& r, Comp comp={}, Proj proj={});
      (2)(since C++20)

      Constructs aheap with respect tocomp andproj from the elements in the specified range.

      1) The specified range is[firstlast).
      2) The specified range isr.

      The function-like entities described on this page arealgorithm function objects (informally known asniebloids), that is:

      Contents

      [edit]Parameters

      first, last - the iterator-sentinel pair defining therange of elements to modify
      r - therange of elements to modify
      comp - comparator to apply to the projected elements
      proj - projection to apply to the elements

      [edit]Return value

      1)last
      2)ranges::end(r)

      [edit]Complexity

      At most\(\scriptsize 3\cdot N\)3·N applications ofcomp and\(\scriptsize 6\cdot N\)6·N applications ofproj, where\(\scriptsize N \)N is:

      1)ranges::distance(first, last)
      2)ranges::distance(r)

      [edit]Example

      Run this code
      #include <algorithm>#include <cmath>#include <functional>#include <iostream>#include <vector> void out(constauto& what,int n=1){while(n-->0)std::cout<< what;} void print(auto rem,constauto& v){    out(rem);for(auto e: v)        out(e), out(' ');    out('\n');} void draw_heap(constauto& v){auto bails=[](int n,int w){auto b=[](int w){ out("┌"), out("─", w), out("┴"), out("─", w), out("┐");};if(!(n/=2))return;for(out(' ', w); n-->0;)            b(w), out(' ', w+ w+1);        out('\n');}; auto data=[](int n,int w,auto& first,auto last){for(out(' ', w); n-->0&& first!= last;++first)            out(*first), out(' ', w+ w+1);        out('\n');}; auto tier=[&](int t,int m,auto& first,auto last){constint n{1<< t};constint w{(1<<(m- t-1))-1};        bails(n, w), data(n, w, first, last);}; constint m{static_cast<int>(std::ceil(std::log2(1+ v.size())))};auto first{v.cbegin()};for(int i{}; i!= m;++i)        tier(i, m, first, v.cend());} int main(){std::vector h{1,6,1,8,0,3,3,9,8,8,7,4,9,8,9};    print("source: ", h);     std::ranges::make_heap(h);    print("\n""max-heap: ", h);    draw_heap(h);     std::ranges::make_heap(h,std::greater{});    print("\n""min-heap: ", h);    draw_heap(h);}

      Output:

      source: 1 6 1 8 0 3 3 9 8 8 7 4 9 8 9 max-heap: 9 8 9 8 8 4 9 6 1 0 7 1 3 8 3       9   ┌───┴───┐   8       9 ┌─┴─┐   ┌─┴─┐ 8   8   4   9┌┴┐ ┌┴┐ ┌┴┐ ┌┴┐6 1 0 7 1 3 8 3 min-heap: 0 1 1 8 6 3 3 9 8 8 7 4 9 8 9       0   ┌───┴───┐   1       1 ┌─┴─┐   ┌─┴─┐ 8   6   3   3┌┴┐ ┌┴┐ ┌┴┐ ┌┴┐9 8 8 7 4 9 8 9

      [edit]See also

      checks if the given range is a max heap
      (algorithm function object)[edit]
      finds the largest subrange that is a max heap
      (algorithm function object)[edit]
      adds an element to a max heap
      (algorithm function object)[edit]
      removes the largest element from a max heap
      (algorithm function object)[edit]
      turns a max heap into a range of elements sorted in ascending order
      (algorithm function object)[edit]
      creates a max heap out of a range of elements
      (function template)[edit]
      Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/algorithm/ranges/make_heap&oldid=180705"

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