AtCoder ABC #075

abc075-a.rb

a, b, c = gets.chomp.split(" ").map(&:to_i)
if a == b
  puts c
elsif b == c
  puts a
else
  puts b
end

abc075-b.rb

H, W = gets.chomp.split(" ").map(&:to_i)
@m = []
@ans = Array.new(H){Array.new(W, 0)}

bomb = []
H.times do |i|
  row = gets.chomp.split("")
  W.times do |j|
    if row[j] == "#"
      @ans[i][j] = row[j]
      bomb << [i, j]
    end
  end
  @m << row
end

d = [[0, -1], [1, -1], [1, 0], [1, 1], [0, 1], [-1, 1], [-1, 0], [-1, -1]]
bomb.each do |i, j|
  d.each do |dx, dy|
    nx = j + dx
    ny = i + dy
    if nx >= 0 && nx < W && ny >= 0 && ny < H && @m[ny][nx] == "."
      @ans[ny][nx] += 1
    end
  end
end
@ans.each do |row|
  puts row.join("")
end

abc075-c.rb

N, M = gets.chomp.split(" ").map(&:to_i)
node = Struct.new("Node", :to)

edges = []
M.times do
  edges << gets.chomp.split(" ").map(&:to_i)
end

# Union Find

def find(x)
  if @par[x] == x
    return x
  else
    @par[x] = find(@par[x])
    return @par[x]
  end
end

def unite(x, y)
  x = find(x)
  y = find(y)
  if x == y
    return
  end
  if @rank[x] < @rank[y]
    @par[x] = y
  else
    @par[y] = x
    if @rank[x] == @rank[y]
      @rank[x] += 1
    end
  end
end

def same(x, y)
  return find(x) == find(y)
end

ans = 0
M.times do |i|
  @g = Array.new(N+1){node.new([])}
  @par = (0..N).to_a
  @rank = Array.new(N+1, 0)
  M.times do |j|
    next if i == j
    a, b = edges[j]
    @g[a].to << b
    @g[b].to << a    
  end
  (1..N).each do |n1|
    @g[n1].to.each do |n2|
      unite(n1, n2)
    end
  end
  nroot = 0
  (1..N).each do |root|
    if root == @par[root]
      nroot += 1
    end
  end
  if nroot != 1
    ans += 1
  end
end

puts ans