Review 001
Complexity Analysis
Tree Method:

number of levels

number of node per level

work per level
levels:
nodes/level:
work/node:
work/level = nodes / level * work / node
sum_0^{log(n)} n/2^i C0 = O(n)
sum_0^{log(n)} 3^i C0 = O(n)
log(n/2^i) = log(n)  log(2^i) = log(n)