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  1. import std.stdio : writeln;
  2. import std.algorithm.comparison: min;
  3. import std.algorithm.iteration: sum;
  4. import core.time: MonoTime, Duration;
  5.  
  6.  
  7. T[] sum_subranges(T)(T[] input, uint range)
  8. {
  9.     T[] result = new T[(input.length + 1)/range +1];
  10.     if (range == 0)
  11.     {
  12.         return result;
  13.     }
  14.     size_t it;
  15.     for (uint i; i < input.length; i=min(i+range, input.length))
  16.     {
  17.         result[it++] = sum(input[i..min(i+range, input.length)]);
  18.     }
  19.     return result;
  20. }
  21.  
  22. unittest
  23. {
  24.     assert(sum_subranges([1,1,1], 2) == [2, 1]);
  25.     assert(sum_subranges([1,1,1,2,3,3], 2) == [2, 3, 6]);
  26.     assert(sum_subranges([], 2) == []);
  27.     assert(sum_subranges([1], 2) == [1]);
  28.     assert(sum_subranges([1], 0) == []);
  29. }
  30.  
  31.  
  32. int main()
  33. {
  34.     int[1000000] v;
  35.     for (int i=0; i < 1000000; ++i)
  36.         v[i] = i;
  37.     int sum;
  38.     MonoTime beg = MonoTime.currTime;
  39.     for (int i=0; i < 100; i++)
  40.         sum += cast(int)sum_subranges(v,2).length;
  41.     MonoTime end = MonoTime.currTime;
  42.     writeln(end-beg);
  43.     writeln(sum);
  44.     return sum;
  45. }
  46.  
Runtime error #stdin #stdout 1.83s 19576KB
comments (?)
stdin
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Standard input is empty
stdout
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1 sec, 832 ms, 325 μs, and 7 hnsecs
50000100
https://ideone.com/h4fnsD
language:
D (gdc 8.3)
created:
6 years ago
visibility:
public

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