Cheat sheet · Class 12 · CBSE · Science Computer Science
Alorithms cheat sheet
The whole chapter on one page: key formulas, facts and the points to remember, for quick revision before a test.
CBSE Class 12 · Computer Science
Cheat sheet
Chapter 2Algorithms
Good algorithm: correct, finite, efficient — measured by Big-O.
1. Characteristics
- input
- output
- definiteness
- finiteness
- effectiveness
2. Complexity
| Big-O | Name | Example |
|---|---|---|
| O(1) | constant | access a list element |
| O(log n) | logarithmic | binary search |
| O(n) | linear | linear search |
| O(n log n) | linearithmic | efficient sorting |
| O(n²) | quadratic | bubble sort |
3. Analysing
- Count key operations as input grows.
- Best, average, worst case.
- Space complexity: extra memory used.
4. Key Points
- Drop constants in Big-O.
- Loops inside loops often mean O(n²).
- Halving the input each step means O(log n).
- Correctness first, then efficiency.
Remember: 5 characteristics | Big-O table | best/worst case
Alorithms: questions and notes
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