java - O-notation with for-loop with modulo condition -
my question how calculate o-notation operation, 2 outer loops go o(n^3) times. question o-notation going when modulo used in condtion , inner for-loop runs when factor in j.
for(int = 1 ; <= n ; i++) { for(int j =1; j <= ∗ ; j++) { if(j % == 0 ) { for(int k = 0 ; k < j ; k++ ){ sum++; } } } }
it o(n^4)
.
the trick 1 if (j % == 0)
. since i
pretty n
, j
going range n^2
know statement true n + (n-1) + ... + 1
times going simplify (n+1)(n+2)/2
or o(n^2)
in turn run loop runs n^2
times. need treat addition, have n^3 + n^2 * n^2
, simplifies o(n^4)
.
if there fault in reasoning please point out, little rusty.
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