1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
|
Task 1: "Maximum Sub-Matrix
You are given m x n binary matrix having 0 or 1 elements.
Write a script to find out maximum sub-matrix having only 0.
Example 1:
Input : [ 1 0 0 0 1 0 ]
[ 1 1 0 0 0 1 ]
[ 1 0 0 0 0 0 ]
Output: [ 0 0 0 ]
[ 0 0 0 ]
Example 2:
Input : [ 0 0 1 1 ]
[ 0 0 0 1 ]
[ 0 0 1 0 ]
Output: [ 0 0 ]
[ 0 0 ]
[ 0 0 ]
"
My notes: dull but easy. No opportunity for cleverness.
Task 2: "Minimum Platforms
You are given two arrays of arrival and departure times of trains at a
railway station.
Write a script to find out the minimum number of platforms needed so
that no train needs to wait.
Example 1:
Input: @arrivals = (11:20, 14:30)
@departures = (11:50, 15:00)
Output: 1
The 1st arrival of train is at 11:20 and this is the only train at the station,
so you need 1 platform. Before the second arrival at 14:30, the first train
left the station at 11:50, so you still need only 1 platform.
Example 2:
Input: @arrivals = (10:20, 11:00, 11:10, 12:20, 16:20, 19:00)
@departures = (10:30, 13:20, 12:40, 12:50, 20:20, 21:20)
Output: 3
Between 12:20 and 12:40, there would be at least 3 trains at the station,
so we need minimum 3 platforms."
My notes: nice problem - looks like a tiny discrete event simulation.
Build a DIARY: an array of (time, type) pairs - where type == 'A' for
an arrival, or type == 'D' for a departure. Then walk the diary,
simulating "train arrival" and "train departure" events.
|
