The professor gave us a few examples to try at home but never gave us the answers and now when revising for the exams I would really like to go a bit more into detail with this. We have 3 "algorithms" and we have to work out the big O for these algorithms.
1st one:
sum <- 0
for i=1 to N do
for j=1 to i do
sum = sum + 1
Since the for loops of this look a lot like the bubble sort loops I came to the conclusion it is O(n^2).
2nd example:
sum <- 0
for i=1 to N do
for j=1 to i*i do
for k=1 to j do
sum = sum + 1
I estimated this should be O(n^5).
3rd example:
sum <- 0
for i=1 to N do
for j=1 to i*i do
if j mod i = 0 then
for k=1 to j do
sum = sum + 1
I think this one would be O(n^4) because the third inner loop will run only Ni instead of Ni*i. Any comments are appreciated. Thanks in advance.
