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  1. #include <iostream>
  2. #include <vector>
  3. #include <iterator>
  4. #include <algorithm>
  5.  
  6.  
  7.     // function to interleave ranges, you'll see the usage later
  8.     template <class InputIterator1, class InputIterator2, class OutputIterator>
  9.       OutputIterator interleave(InputIterator1 first1, InputIterator1 last1,
  10.                             InputIterator2 first2, InputIterator2 last2,
  11.                             OutputIterator result)
  12.     {
  13.       while (first1 != last1 || first2 != last2) 
  14.       {
  15.         if (first1==last1) return std::copy(first2,last2,result);
  16.         if (first2==last2) return std::copy(first1,last1,result);
  17.  
  18.         *result++ = *first1++;
  19.     	*result++ = *first2++;
  20.       }
  21.     }
  22.  
  23.     int main() // example
  24.     {
  25.         std::vector<int> v {1, 2, 3, 4, 5, 6, 7};
  26.         // fill v with elements
  27.         std::vector<int> result; // this is not an "in place solution"
  28.  
  29.         interleave(v.begin(), v.end(), v.rbegin(), v.rend(), back_inserter(result));
  30.         // result holds the answer - keep that or assign it back to v
  31.         std::cout << "v = ";
  32.         for (int i : v) std::cout << i << ", ";
  33.         std::cout << std::endl;
  34.  
  35.         std::cout << "result = ";
  36.         for (int i : result) std::cout << i << ", ";
  37.         std::cout << std::endl;
  38.     }
Success #stdin #stdout 0s 3472KB
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Standard input is empty
stdout
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v = 1, 2, 3, 4, 5, 6, 7, 
result = 1, 7, 2, 6, 3, 5, 4, 4, 5, 3, 6, 2, 7, 1,
https://ideone.com/DMVnlp
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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