Peter :
The time complexity for this method is O(2^n)
according to my prof.
I feel that the time complexity for this method should be O(n * 2^n)
because
The outer for loop cost O(n)
The inner for loop cost O(2^n)
public static int loop(int n) {
int j = 1;
for (int i = 0; i < n; i++) {
for (int k = j; k > 0; k--) {
System.out.println("Hello world");
}
j *= 2;
}
return j;
}
SomeDude :
Consider this:
For i = 0
: j = 1 -> 2^0
For i = 1
: j = 2 -> 2^1
For i = 2
: j = 4 -> 2^2
For i = 3
: j = 8 -> 2^3
....
For i = n-1
: j = 2^n-1
If you add all of those :
2^0 + 2^1 + 2^2 +.....+2^(n-1) => order of 2^(n) -> 2^(n) - 1 to be precise
So the time complexity is O(2^n)