Abhishek Dubey1 month agoMost voted6
Don't go top down, build up from the base case:
f(0)=1, f(1)=1, f(2)=2, f(3)=3, f(4)=5
Much faster than a tree.
int f(int n) {
if (n <= 1) return 1;
return f(n-1) + f(n-2);
}f(4)? I keep messing up when drawing the full tree under time pressure
2 answers
aman khan1 month ago2
its just fibonacci shifted. quiz setters love hiding fibonacci
Related questions
- 2answers 4votes recursion samajh nahi aata yaar base case aur recursive call theek hai but tree recursion me (like subsets) dimag kharab ho jata hai. kaise practice karu DSARahul Yadav·21 days ago
- 2answers 10votes how to know when to use binary search on answer Koko eating bananas, ship packages in D days etc. I understand the solution after seeing it but I never recognise these in a new problem DSAAditya Verma·27 days ago
- 3answers 5votes Striver sheet or Leetcode 75? 4 months left. which one should I do DSARitika Malhotra·28 days ago
- 2answers 7votes Complexity when inner loop starts from i for (int i = 0; i < n; i++) for (int j = i; j < n; j++) count++; Answer was O(n^2). But the inner loop runs fewer times every iteration so shouldn't it be less… DSAAbhishek Dubey·2 months ago
Want the full explanation, not just an answer?
Structured lessons on DSA, core CS, Java and interview skills, each ending in a quiz so you know it stuck.