Tenth Week

                               3rd Nov ~ 7th Nov

• O(n²) 
• Ω(n²)
• ϴ(n²)

  "when finding upper-bound, it is OK to over-estimate the number of steps"

"when finding lower-bound, it is OK to under-estimate the number of steps".This two sentences are very useful in dealing with such kind of finding O problem, which should always be kept in our mind.

This problem and solution really make me learn a lot. If we want to make aconnection between two steps we could overestimate one and underestimate the other and choose a c that could reveal their relationship explicitly with <= or >=.