The first call to Lambda Function by std::accumulate uses the initial value 0 as 'a' and the first element of the vector as 'b'.

for these ex : std::vector{-1, 2, 3, 4, -5};

first imple : a = 0, b = -1 ==> resul a + std::max(0, b) = 0 + 0 = 0; then store the result to a.

Second imple : a = 0, b = 2 ==> resul a + std::max(0, b) = 0 + 2 = 2; then store the result to a.
.....

The STL has built-in stuff for a reason. This is exactly what this function is used for.

whats part you didnt get it ?

I can't understand this solution

I can't understand this solution

yeah, but at some point parallel execution_police becomes benefitial

P.S. we would have to replace accumulate with reduce

max(0, b) is very clever!

this approach is interessant from STL perspective but less performant than iterating through the vector with for() loop

or kill a mosquito using a cannon.

I was wondering what the point of the higher order function was, but clearly it turned 4 lines of repeated code into 1. Had to change my solution to this one!

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