Accumulation of subsequences of a sequence using C#/Linq

Question

I\'m trying to find a better way of processing a sequence of numbers based on the following requirement: the value of sequence[i] is the sum of its own value pl

Answer 1

Here is another way similar to one of the posts, but this one is self-contained:

// C#
Enumerable.Range(1, 100)
.Aggregate(new List{0},
  (acc, x) => { acc.Add(acc.Last() + x); return acc; })
.Dump(); // Dump using LINQPad; ans: 5050

If we switch to int64, and use 10,000,000 as the upper bound, and read the final accumulated result, the code executes in about 450 milli-seconds on a Corei5 with a final output of:

50000005000000

Incidentally, for an upper bound of 1,000,000 the execution is about 40 milli-seconds, so increasing the size by 10 increased the time by 10.