Reduce number of loops in tracker

[ZhiyuanChen]

Slightly increase spped by reducing two for loop to one

[alexnguyen2201]

@zyc-ai a comprehension list is faster than a loop

[ZhiyuanChen]

a comprehension list is faster than a loop

It seems not in the case of Python https://stackoverflow.com/a/43677631/8791650.

[kanasite]

a comprehension list is faster than a loop

It seems not in the case of Python https://stackoverflow.com/a/43677631/8791650.

I beg to diff, consider doing this instead

def square_sum4(numbers): return(sum([i**2 for i in numbers]))