count the character and create a histogram

Booking.com Interview Questions
Booking.com Interview Questions Software Engineer
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1. Histogram
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You have the file with a list of words at a single line.
#input sample file
abactor
abaculus
abacus
Abadite
.
.
Zyrenian
#Output
******************************************************************a
*************b
**********************************c
**********************d
*******************************************************************************e
a) you have to count the character and create a histogram in alphabetical order.
b) now you have to produce a histogram with max 80 character in line in reference to max count
c) now same out based histrogram based on the character count
- madeinindia on March 24, 2014 in neitherland for perl backe
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Algorithm:
Read file lines
Initialise character_hash
Accept only ENGLISH LATIN CHARATERS
Buillt character_hash
Find_Maximum_occurence (if bigger than 80 normlise maximum)
Print hystogram
http://eftpos-test.telekomcloud.hr/cgi-bin/mercur_histogram.cgi


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Multisets intersection
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"A Multiset is a set where repetitions are allowed (ex: MS1 = (1,1,2,2,2,3,3,4,4,4,4,4,5,7,7,9...).
Problem: write a program that receives two Multisets and returns intersections
(element 2 appears three times on MS1 and five times on MS2 then intersection should contain the element three times."
@ms1 = (1,1,2,2,2,3,3,4,4,4,4,4,5,7,7,9);
@ms2 = (2,3,3,3);
@intersection = (2,3,3,3);
Algorithm:
1. built 2 hashes ms1 and ms2
2. loop through each key and print minimum =min(ms1{key},ms1{key});
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2. Picture compression
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"Given an array of colors to represent an image (each element being a pixel color) ex.: (1,1,1,2,2,55,55,55,238,238,238,238,91,91,91,2,2,2,2,1,4,7,7,7,12,127) write a program that compress it."

Part of a Software Developer Interview Review - one of 139 Booking.com Interview Reviews
Result should contain pairs element,repetitions.
Worst case would double the size of resulting array.
Answer to example would be:
(1,3,2,1,55,3,238,4,91,3,2,4,1,1,4,1,7,3,12,1,127,1)


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3. sort data structure by score
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You have data structure
my $users = [
{ name => 'John', score => 10, },
{ name => 'Bob', score => 1, },
{ name => 'Carlos', score => 5 },
{ name => 'Alice', score => 5, },
{ name => 'Donald', score => 7 }
];
now u have to arrange the name with highest to lower score, if score is same than in alphabetical order #expected output: # John # Donald # Alice # Carlos # Bob"

my %hash = () ;
foreach (@$users) {
$hash{$_->{name}} = $_->{score};
}
foreach (sort {$hash{$b} <=> $hash{$a}} keys %hash ) {
print "$_\n";
}
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"Symmetric Difference of Arrays"
Input: two arrays of integers
Output: one array of integers
which occur in only one (not both) arrays
Test case:
Input A: [ 1, 7, 8, 2, 4, 5 ]
Input B: [ 3, 5, 1, 7, 6, 9 ]
Output: [ 8, 2, 4, 3, 6, 9 ]
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write a regular expression for zip codes.

Second question was to write a program that takes two integer arrays and output the elements in two arrays and eliminate the duplicates. e.g [1, 2, 3, 4] and [3, 4, 5, 6] should output [1, 2, 3, 4, 5, 6]

Third question was to write down a bash script that mimics the find command that takes a root directory and file name and searched for that file name within this directory and enclosed subdirectory.

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Array intersection
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"If you are given 2 array A={3,1,2,4} B={1,4}. Write a program to compare two arrays and create another array which holds the common values between two array!"

#!/usr/bin/perl
my @a = ('3','1','2','4','44');
my @b = ('23','44','1','4');
my @res;
my %a_hash =();
foreach (@a) {
++$a_hash{$_};
};
foreach (@b) {
if ($a_hash{$_} >0) {push @res; };
};

print "Common values @res\n";
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