Description
One Day Assignment 8 – Islands
• Easier way of looping through all 4 directions (instead of hardcode):
• int[][] move = {{-1, 0}, {0, 1}, {1, 0}, {0, -1}};
• for (int i = 0; i < 4; i++) {
• int nextRow = row + move[i][0];
• int nextCol = col + move[i][1];
• // check for out of bounds etc. here
• }
• The above code traverses up, right, down and left, in that order
Lab 10 – MST
• Two different forms of MST algorithms are covered: Prim’s and
Kruskal’s
• Prim’s tends to be used alongside an Adjacency List (or an Adjacency Matrix in
the cases of near complete graphs), while Kruskal’s tends to be used alongside
an Edge List
• Prim’s uses a priority queue as well, while Kruskal’s uses a UFDS
• Examples provided in lectures
Take Home Assignment 4 – Millionaire
Madness
• Uses a 2D grid (code example for moving up/down etc. may help)
• Need to reach the lower right corner of the grid from the upper left
corner
• Each cell has a specific height
• A ladder is needed when going up in height (the length of the ladder
must be >= the difference in height)
• A ladder is not required when going down in height
• Find the minimum ladder length needed
Take Home Assignment 4 – Millionaire
Madness
• Route for last sample input (red -> blue -> green, endpoints in bold):
• 10 11 12 13 14
11 20 16 17 16
12 10 18 21 24
14 10 14 14 22
16 18 20 20 25
25 24 22 10 25
26 27 28 21 25
• Can be solved via correct graph modelling and a specific MST
algorithm
Take Home Assignment 4 – Millionaire
Madness
Take Home Assignment 4 – Dominos
• Knocking down one domino manually may result in a few other
dominos being knocked down as well
• These dominos may in turn cause other dominos to knock over as
well
• Find the minimum number of dominos that must be knocked down
manually so that all dominos are knocked down
• Trying to visualise the solution on a general graph might be difficult;
can consider converting the graph to a specific type of graph that’s
simpler to visualise with
One Day Assignment 9 – Lost Map
• Given the shortest path (in terms of distance) between any two
villages on a map, find all the roads that make up the original set of
roads
• Graph is a complete graph, and hence consists of a lot of edges
• The following information is given (explicitly, or deduced from the
problem description):
• The original set of roads form a connected, weighted tree
• Distance of any road (u, v) in the map is > 0, unless (u == v)
• Note: using Scanner can still work here, but it is recommended to use
buffered IO for this problem (saves 3+ seconds of CPU time, out of 8)