By: Saurav
2017-12-29 20:48:00 UTC
Consider a staircase of size 4:
#
##
###
####
Observe that its base and height are both equal to 4, and the image is drawn using # symbols and spaces. The last line is not preceded by any spaces.
Write a program that prints a staircase of size n.
Input Format
A single integer,n, denoting the size of the staircase.
Output Format
Print a staircase size n using # symbols and spaces.
Note: The last line must have 0 spaces in it.
Sample Input
6
Sample Output
#
##
###
####
#####
######
Explanation
Although above its being shown left aligned, the staircase is right-aligned, composed of # symbols and spaces, and has a height and width of 6.
This an easy but interesting problem where number of spaces is decreasing and number of # are increasing.
Going through our steps to solve any algo problems, we see clearly, there is a mathematical pattern between these two where the sum is always equal to n but space number is decreasing and # number is increasing.
n = gets.to_i
def build_the_tree(n)
return "" if n < 1
j = 1
(0..n-1).each do |i|
puts get_spaces(n-j) + get_hashes(j)
j+=1
end
return
end
def get_spaces(n)
str = ""
(0..n-1).each do |i|
str += " "
end
return str
end
def get_hashes(n)
str = ""
(0..n-1).each do |i|
str += "#"
end
return str
end
build_the_tree(n)
lets clean it a little and remove repetitions.
n = gets.to_i
def build_the_tree(n, j = 1)
return "" if n < 1
(0..n-1).each do |i|
puts get_pattern(n-j, " ") + get_pattern(j, "#")
j+=1
end
end
def get_pattern(n, pattern, str = "")
(0..n-1).each do |i|
str += pattern
end
return str
end
build_the_tree(n)
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