- Examples: additions, multiplications, comparisons
- Constant time per line of pseudocode
- In reality each operation takes different amount of time
- Best Case: constraints on the input, other than size, resulting
in the fastest possible running time
- Worst Case: constraints on the input, other than size, resulting
in the slowest possible running time
- Average Case: average running time over every possible type of input (usually involves probabilities of different types of input)