关键词 > COMP4600/8460
COMP4600/8460 - Advanced Algorithms S2 2022 Assignment 3
发布时间:2022-09-18
Hello, dear friend, you can consult us at any time if you have any questions, add WeChat: daixieit
COMP4600/8460 - Advanced Algorithms
S2 2022
Assignment 3
1 Questions
Q1) (5 Marks) Let Sn be a binomial random variable BIN(n,p)
Apply Chernoff bound to prove for any 0 < δ < 1 that
P (Sn ≥ (1 + δ)np) ≤ e
P (Sn ≤ (1 − δ)np) ≤ e
Q2) (5 Marks) There are n balls thrown independently and uniformly at random into n bins
1. Show the probability that a particular bin receiving at least M balls is at most (M(n))()M
2. Show the probability that all n bins have at most M balls is at most n()
Note: Do not use Poisson approximation
Q3) (5 Marks) Given a set of strings S = {s1 , ...,sn }, map each string to a bit-string using m bits by an ideal hashing function, such that each bit has an equal probability of being 0 or 1. Then we use the set of bit-strings B = {b1 , ...,bn } to test if a string is a member of S or not
1. Show m = Ω(log n) bits is necessary for the probability of a false positive to be lesser than 1
2. Show m = O(log n) bits is sufficient for the probability of a false positive to be at most Q4) (2.5 Marks) Let Sn be BIN(n,p). Prove the tail probability is bounded by P(Sn ≥ enp) ≤ e −np
Q5) (2.5 Marks) Let X be the number of draws required to collect all n types of coupons. Prove, for any constant c,
lim P(X > nlnn + cn) = 1 − e −e − c
n →∞
You can use Poisson approximation
Q6) (10 Marks) Simulate balls-and-bins model and power of d-choices model, and compare their empirical maximum loads under various values of m (≤ 10000), n (≤ 10000) and d (≤ 10). Implement your simulation in Python/Java/C. Plot and discuss the results here in this report, and upload your code separately on Wattle
2 Answers
...
References
[MU] Mitzenmacher & Upfal, Probability and Computing, Cambridge University Press, (2017).