I need output of Floyd triangle like:
1
0 1
1 0 1
0 1 0 1
I tried. I didn't get it exactly. Can anyone explain the logic?
This is the code I tried:
k = 0
for i in 1..5
for j in 1..5
if (i%2)==0;
k = (j%2==0) ? 1:0;
else;
k = (j%2==0) ? 0:1;
puts k,'';
end
end
puts
end
The main issue here is that in order to get the "triangle" shape of your output, you need your inner loop to increment from 1 to i instead of 1 to 5.
k = 0
for i in 1..5
for j in 1..i
if (i%2)==0
k = j + 1
else
k = j
end
print "#{k%2} "
end
puts
end
Here's a one line approach:
5.times {|line| puts (line + 1).times.with_object(""){|num, str| (num + line).even? ? (str << " 1 ") : (str << " 0 ") } }
to make it more clear:
lines = 5
lines.times do |line|
str = ""
line = line + 1 # 5.times runs from 0 to 4 and we need 1 to 5
line.times do |num|
# the condition is a bit different because I changes the code a bit
if (line + num).even?
str << " 0 "
else
str << " 1 "
end
end
puts str
end
Alright the following should work, but i hope it's readable. If you need more explanation or have specific questions let me know
i = 1
while i <= 4 do
if i%2 > 0
output = 1
else
output = 0
end
j = 1
while j <= i do
print( "#{output} " )
if output == 1
output = 0
else
output = 1
end
j+=1
end
print( "\n" )
i+=1
end
You can try following code for output you are expecting:
k = 0
for i in 1..4
for j in 1..i // inner loop code runs i times for each outer loop iteration
if (i%2)==0;
k = (j%2==0) ? 1:0;
else;
k = (j%2==0) ? 0:1;
end
print k,' ';
end
puts
end
Click Here to see output.
You can also get idea about for loops through this link.
The prefered ruby way:
layers = 4 # Change to as many layers as you want
layers.times do |i| # i starts from 0
(i + 1).times do |j| # j also starts from 0
print (i + j + 1) & 1, ' '
end
puts
end
The for way:
layers = 4
for i in 0...layers
for j in 0...(i + 1)
print (i + j + 1) & 1, ' '
end
puts
end
Related
Invoice numbers are numeric only with any number of digits. To format one correctly, group the digits in group of three plus a group of any remainder, but never leave one digit by itself, unless it's a one digit number. Eg these are all correct formatting
123
12-34
6
783-907-23-45
And these are not
123-4
98-456
There's one more catch user input is passed directly to the function and you never know what characters users might type. Ignore any part of the input that is not digit
Invoice.format_number should always return a string
module Invoice
def self.format_number(str)
return ""
end
end
puts Invoice.format_number("ab1234")
What I have tried
1st approach
arr = []
str.chars.each do |elem|
val = elem =~ /\A[-+]?[0-9]*\.?[0-9]+\Z/
arr << elem if val == 0
end
num_of_digits = arr.length
pairs_of_two = 0
pairs_of_three = 0
if num_of_digits > 5
while num_of_digits > 0 do
break if num_of_digits <= 3
if num_of_digits >= 3 && (num_of_digits % 3 == 0 || num_of_digits % 3 == 2)
pairs_of_three += 1
num_of_digits -= 3
elsif num_of_digits % 2 == 0 || num_of_digits % 2 == 1
pairs_of_two += 1
num_of_digits -= 2
end
end
end
2nd approach
arr = []
str.chars.each do |elem|
val = elem =~ /\A[-+]?[0-9]*\.?[0-9]+\Z/
arr << elem if val == 0
end
len = arr.length - 1
if arr.length > 4
str = ""
i = 0
while i < len do
if arr[i..i+3].length == 4
str << arr[i..i+2].join + "-"
i += 3
elsif arr[i..i+2].length == 3
str << arr[i..i+1].join + "-"
i += 2
elsif arr[i..i+1].length == 2
str << arr[i..i+1].join
i += 2
elsif !arr[i].nil?
str << arr[i]
i += 1
end
end
puts str
else
if arr.length <= 3
puts arr.join
else
puts arr[0..1].join + "-" + arr[2..3].join
end
end
But none of them is correct
Here is the function invoice_number in python
def invoice_number(invoice):
s = ''.join(x for x in invoice if x <= '9' and x >= '0')
n = len(s)
if n <= 3:
return s
w = ''
i = 0
while i + 3 <= n:
for j in range(0, 3):
w += s[i + j]
i += 3
w += ('-')
m = n - i
if m == 0: return w[:-1]
if m == 1: return w[:m-3] + '-' + s[-2:]
return w + s[i:]
Testing
print(invoice_number('1234567'))
print(invoice_number('12345678'))
print(invoice_number('abc123456789'))
print(invoice_number('1234abc5678xyz9foobar'))
123-45-67
123-456-78
123-456-789
123-456-789
Eliminating non-digits is easy with re. For your format, the key is to figure our the "right" splitting indices.
Here is a try:
import re
def splits(n, k):
idx = [(i, min(n, i+k)) for i in range(0, n, k)]
if len(idx) > 1:
(a, b), (c, d) = idx[-2:]
if d - c < 2:
idx[-2:] = [(a, b - 1), (c - 1, d)]
return idx
def myformat(s):
s = re.sub(r'[^0-9]+', '', s)
parts = [s[a:b] for a, b in splits(len(s), 3)]
return '-'.join(parts)
Tests:
>>> myformat('123')
123
>>> myformat('1234')
12-34
>>> myformat('6')
6
>>> myformat('7839072345')
783-907-23-45
As the question was asked for ruby, adding solution for ruby. (The inspiration of the code is mostly from #yuri answer)
def format_invoice(invoice)
# only numbers are allowed
invoice = invoice.tr("^0-9","")
#puts invoice
return invoice if(invoice.length <= 3)
formatted_invoice = ''
i = 0
# Loop to divide the invoice in group of 3
while i + 3 <= invoice.length do
for j in 0..2 do
formatted_invoice += invoice[i + j]
end
i += 3
formatted_invoice += ('-')
end
m = invoice.length - i
return formatted_invoice[0..-2] if m == 0
return formatted_invoice[0..m-4] + '-' + invoice[-2..-1] if m == 1
return formatted_invoice + invoice[i..-1]
end
Testing
puts format_invoice('abc1') # 1
puts format_invoice('abc123') # 123
puts format_invoice('abc123A4') # 12-34
puts format_invoice('1234567') # 123-45-67
puts format_invoice('12345678') # 123-456-78
puts format_invoice('abc123456789') # 123-456-789
puts format_invoice('1234a#c5678xyz9foobar') # 123-456-789
This script is for Project Euler #14
I am refactoring it and all I did was grab 1 line of code n.even? ? n = n/2 : n = (3*n) + 1 and made it into it's own function. This change increase the execution time by 5 seconds.
Why would that happen?
Before:
def longest_collatz_sequence1(count)
check = []
while count >= 1
n = count
seq = [count]
while n > 1
n.even? ? n = n/2 : n = (3*n) + 1
seq << n
end
count -= 1
check << seq
value = sequence_check(check) if check.length == 2
end
puts "The number that produces the largest chain is: #{value[0][0]}"
end
def sequence_check(check)
check[0].length > check[1].length ? check.delete_at(1) : check.delete_at(0)
check
end
s = Time.new
longest_collatz_sequence1 1000000
puts "elapsed: #{Time.new-s}"
#~12.2 seconds
After:
def longest_collatz_sequence1(count)
check = []
while count >= 1
n = count
seq = [count]
while n > 1
n=collatz(n)
seq << n
end
count -= 1
check << seq
value = sequence_check(check) if check.length == 2
end
puts "The number that produces the largest chain is: #{value[0][0]}"
end
def collatz(n)
n.even? ? n = n/2 : n = (3*n) + 1
end
def sequence_check(check)
check[0].length > check[1].length ? check.delete_at(1) : check.delete_at(0)
check
end
s = Time.new
longest_collatz_sequence1 1000000
puts "elapsed: #{Time.new-s}"
#~17.7 seconds
if i run the code, it will stop and not do anything and i am unable to type. seems to be an infinite loop.
the problem seems to be the end until loop, however if i take that out, my condition will not be met.
can anyone find a solution? i have tried all the loops that i can think of.
/. 2d array board ./
board = Array.new(10) { Array.new(10, 0) }
/. printing board ./
if board.count(5) != 5 && board.count(4) != 4 && board.count(3) != 3
for i in 0..9
for j in 0..9
board[i][j] = 0
end
end
aircraftcoord1 = (rand*10).floor
aircraftcoord2 = (rand 6).floor
aircraftalign = rand
if aircraftalign < 0.5
for i in 0..4
board[aircraftcoord2+i][aircraftcoord1] = 5
end
else
for i in 0..4
board[aircraftcoord1][aircraftcoord2+i] = 5
end
end
cruisercoord1 = (rand*10).floor
cruisercoord2 = (rand 7).floor
cruiseralign = rand
if cruiseralign < 0.5
for i in 0..3
board[cruisercoord2+i][cruisercoord1] = 4
end
else
for i in 0..3
board[cruisercoord1][cruisercoord2+i] = 4
end
end
destroyercoord1 = (rand*10).floor
destroyercoord2 = (rand 8).floor
destroyeralign = rand
if destroyeralign < 0.5
for i in 0..2
board[destroyercoord2+i][destroyercoord1] = 3
end
else
for i in 0..2
board[destroyercoord1][destroyercoord2+i] = 3
end
end
end until board.count(5) == 5 && board.count(4) == 4 && board.count(3) == 3
print " "
for i in 0..9
print i
end
puts
for i in 0..9
print i
for j in 0..9
print board[i][j]
end
puts
end
The line board.count(5) == 5 ... will never be true because board is a two-dimensional array. I can't tell what the condition should be, but it could look something like:
board[5].count(5) == 5
I'm trying to do in the Ruby program the summation of a factorial. and I can not solve. a clarification, when they run out points .... means that the logic is fine. if you get a F in one of the points, it means that the logic is wrong.
Write a program to calculate the sum of 1 + 1 / (2!) + 1 / (3!) + 1 / (4!) + .... + 1 / (n!) For a given n. Write the program in two ways: using While, For
def factorial(n)
#(n == 0) ? 1 : n * factorial(n - 1)
fact = 1
for i in 1..n
fact = fact * i
end
return fact
end
def sumatoriaWhile(n)
total = n
sumatoria = 0.0
while n > 1
total = total * (n - 1)
n = n - 1
sumatoria =sumatoria + total.to_f
end
return (1 + (1 / total.to_f)).round(2)
end
def sumatoriaFor(n)
fact = 1
sumatoria = 0.0
for i in 1..n
for j in 1..i
fact = fact * j
end
sumatoria = sumatoria + (1 / fact.to_f)
i = i + 1
end
return sumatoria.round(2)
end
#--- zona de test ----
def test_factorial
print validate(120, factorial(5))
print validate(5040, factorial(7))
print validate(362880, factorial(9))
end
def test_sumatoriaWhile
print validate(1.50, sumatoriaWhile(2))
print validate(1.83, sumatoriaWhile(3))
end
def test_sumatoriaFor
print validate(1.50, sumatoriaFor(2))
print validate(1.83, sumatoriaFor(3))
end
def validate (expected, value)
expected == value ? "." : "F"
end
def test
puts "Test program"
puts "---------------------------"
test_factorial
test_sumatoriaWhile
test_sumatoriaFor
puts " "
end
test
My friend, Thank you for your prompt response. First of all, I appreciate the help given. I am learning ruby programming and want to learn more as you and the other people. if indeed the answer is wrong. I have modified the answer. and also need to know what the function of While. and I hereby amended program again. and now I get an F on the part of WHILE.
def factorial(n)
fact = 1
for i in 1..n
fact = fact * i
end
return fact
end
def sumatoriaWhile(n)
total = n
sumatoria = 0.0
while n < 1
total = total * (n - 1)
sumatoria = sumatoria + (1.0 / total.to_f)
n = n - 1
end
return sumatoria.round(2)
end
def sumatoriaFor(n)
fact = 1
sumatoria = 0.0
for i in 1..n
fact = fact * i
sumatoria = sumatoria + (1.0 / fact.to_f)
end
return sumatoria.round(2)
end
#--- zona de test ----
def test_factorial
print validate(120, factorial(5))
print validate(5040, factorial(7))
print validate(362880, factorial(9))
end
def test_sumatoriaWhile
print validate(1.50, sumatoriaWhile(2))
print validate(1.67, sumatoriaWhile(3))
end
def test_sumatoriaFor
print validate(1.50, sumatoriaFor(2))
print validate(1.67, sumatoriaFor(3))
end
def validate (expected, value)
expected == value ? "." : "F"
end
def test
puts "Test de prueba del programa"
puts "---------------------------"
test_factorial
test_sumatoriaWhile
test_sumatoriaFor
puts " "
end
test
I have a hard time figuring out what you're doing in the summation function. Here's a straightforward function:
def sumatoriaFor(n)
return 0 if n <= 0
factorial = 1
sum = 0.0
for i in 1..n
factorial *= i
sum += 1.0 / factorial.to_f
end
return sum.round(2)
end
def sumatoriaWhile(n)
return 0 if n <= 0
i = 1
factorial = 1
sumatoria = 0.0
while i <= n
factorial *= i
sumatoria += (1.0 / factorial.to_f)
i = i + 1
end
return sumatoria.round(2)
end
The while look is straight forward too now. Also your validation is wrong:
1 + 1/2 + 1/6 ~= 1 + 0.5 + 0.17 = 1.67
I'm trying to code the 'Sieve of Eratosthenes' in Ruby and I'm having difficulty in the second 'while' loop. I want to test to see if integers[j] % integers[0] == 0, but the compiler keeps giving me a nil:Nil Class error at this line. I can't figure out the problem.
n = gets.chomp.to_i
puts
while n < 2
puts 'Please enter an integer >= 2.'
puts
n = gets.chomp.to_i
puts
end
integers = []
i = 0
while i <= n - 3
integers[i] = i + 2
i += 1
end
primes = []
j = 1
while integers != []
primes.push integers[0]
while j <= integers.length
if integers[j] % integers[0] == 0
integers.delete(integers[j])
end
j += 1
end
integers.shift
j = 1
end
puts integers
puts
puts primes
Thanks in advance for any help!
It's an off-by-one error. You're testing for j <= integers.length. So, for example, if you array has five items, the last iteration will be integers[5]. But the last index in a five-item array is 4 (because it starts at 0). You want j < integers.length.