Solving with Ruby and Crystal AtCoder ABC 129 D

Introduction

• AtCoder Problems * Recommendation is used to solve past problems. Thanks to AtCoder and AtCoder Problems.

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AtCoder Beginner Contest D - Lamp Difficulty: 1103

This theme, transpiler

This problem was previously solved with AtCoder ABC129 D 2D Array in Ruby and Java. It's a speedy issue for Ruby.

This time, when I manually transpiled the Ruby code to the Crystal code, it improved to 1281 ms-> 227 ms. I hope it will be automatically transpiled in the future.

Ruby -> JavaScript Speaking of transpilers in Ruby, Opal While the publication of Ruby-related books is lonely, "Practice Opal" was published in May 2020. However, in competition pros, the speed improvement is considered to be small (because of scripting language-> scripting language). ~~ I'm glad if something goes wrong and it becomes Ruby-> Java ~~ Ruby -> C If you are developing Ruby, you are a master of Ruby and C, so can you do it easily? Ruby -> Go Google secretly develops it Ruby -> Crystal Crystal

Crysta.cr

h, w = read_line.split.map { |c| c.to_i }
s = [] of Array(UInt8)
h.times do
  s << read_line.chomp.bytes
end
hs = [] of Array(Int32)
h.times do |y|
  cnt = 0
  v = [] of Int32
  w.times do |x|
    if s[y][x] == 46
      cnt += 1
    else
      cnt.times do
        v << cnt
      end
      cnt = 0
      v << 0
    end
  end
  cnt.times do
    v << cnt
  end
  hs << v
end
vs = [] of Array(Int32)
w.times do |x|
  cnt = 0
  v = [] of Int32
  h.times do |y|
    if s[y][x] == 46
      cnt += 1
    else
      cnt.times do
        v << cnt
      end
      cnt = 0
      v << 0
    end
  end
  cnt.times do
    v << cnt
  end
  vs << v
end
max = 0
h.times do |i|
  w.times do |j|
    max = hs[i][j] + vs[j][i] if max < hs[i][j] + vs[j][i]
  end
end
puts max - 1

Array.cr

h, w = read_line.split.map { |c| c.to_i }
s = [] of Array(UInt8)

It doesn't feel strange, just the standard input and array initialization have changed. Ruby

Ruby.rb

h, w = gets.split.map(&:to_i)
s = h.times.map { gets.chomp.bytes }
hs = []
s.each do |t|
  cnt = 0
  v = []
  t.each do |x|
    if x == 46
      cnt += 1
    else
      cnt.times do
        v << cnt
      end
      cnt = 0
      v << 0
    end
  end
  cnt.times do
    v << cnt
  end
  hs << v
end
vs = []
s.transpose.each do |t|
  cnt = 0
  v = []
  t.each do |x|
    if x == 46
      cnt += 1
    else
      cnt.times do
        v << cnt
      end
      cnt = 0
      v << 0
    end
  end
  cnt.times do
    v << cnt
  end
  vs << v
end
max = 0
h.times do |i|
  w.times do |j|
    max = hs[i][j] + vs[j][i] if max < hs[i][j] + vs[j][i]
  end
end
puts max - 1

This is the original code.

It's about 5 times faster.

Summary

• Solved ABC 129 D
• Become familiar with Crystal