Analysis of Algorithms

1. Principles:
   Complexity of $\mathcal{O}(n^2)$O(n2) is not feasible. We’d like linear complexity $\mathcal{O}(n)$O(n), or linearithm $\mathcal{O}(nlog(n))$O(nlog(n)).
2. tilde notation $\sim$∼
   The highest order of the complexity with the same coefficient.
   Tilde means the limit of the ratio of the two elements approaches 1.
   eg: $\sim\frac{1}{2}n$∼21​n
3. Best, worst and average time
4. Bound notation
   
5. Memory