You are given two independent interview questions.
1) Triangle minimum path sum (DP)
Given a triangular array triangle with n rows, find the minimum path sum from the top to the bottom.
-
You start at
triangle[0][0]
.
-
From row
i
, column
j
, you may move to row
i+1
at column
j
or
j+1
.
-
Return the minimum possible sum along any valid top-to-bottom path.
Input: A list of lists, where row i has length i+1.
Output: An integer (or numeric) minimum path sum.
Constraints (typical): 1 <= n <= 2000, values may be negative/positive.
2) Two dice stopping problem + Monte Carlo
There are two fair dice:
-
Die A has faces
{1,2,3,4,5}
(a 5-sided die).
-
Die B has faces
{1,2,3,4,5,6}
(a 6-sided die).
The experiment proceeds in rounds. In each round, you roll both dice once.
-
The process
stops
at the first round where
at least one
die shows
1
.
-
In the stopping round:
-
Die A
wins
if
A=1
and
B≠1
.
-
Die B
wins
if
B=1
and
A≠1
.
-
It is a
tie
if
A=1
and
B=1
.
Answer the following:
-
What is the probability that the
5-sided die (Die A) wins
?
-
What is the
expected number of rounds
until the process stops?
-
Implement a
Monte Carlo simulation
to estimate (1) and (2), and discuss how many trials you would run to get a stable estimate.