bparanj

Interval Operations

There are a few operations that can be performed on intervals:
1. Merge  interval[] s.t. the all intervals are disjoint.
		[0,5],[5,7] ==> [0,7]
2. Insert interval into interval[] s.t. all intervals are disjoint.
3. Find intersection between two interval[].
		[0,5],[5,7] => [5,5]

In order to perform these operations, it is important to understand the 6

bparanj

def smaller_numbers_than_current(nums)
  indices = {}
  list = nums.sort
  for i in (0..list.size-1)
    unless indices.has_key?(list[i])
      indices[list[i]] = i  
    end
  end
  result = []
  

bparanj

def two_sum(nums, target)
  hash = {}

  nums.each_with_index do |element, index|
    if hash.include?(target - element)
      return [index, hash[target - element]]
    else
      hash[element] = index
    end
  end

bparanj

def xor_operation(n, start)
  number = 0
  
  for i in (0..n-1) do
    number ^= start + 2*i
  end
  
  number
end

bparanj

def num_jewels_in_stones(j, s)
  jewels = j.chars
  count = 0
  
  s.chars.each do |c|
    if jewels.include?(c)
      count += 1
    end
  end
  count

bparanj

def number_of_steps(num)
	count = 0
	while num != 0
  	if num.even?
  		num = num/2
  	else
  		num -= 1
  	end
    count += 1
	end

bparanj

def defang(address)
  chars = address.chars
  result = ''
  
  chars.each do |c|
    if c == '.'
      c = '[.]'
    end
    result += c
  end

bparanj

def candies(candies, extra_candies)
  max = candies.max
  
  result = []
  
  for i in (0..candies.size-1)
    if candies[i] + extra_candies >= max
      result << true
    else
      result << false

bparanj

def shuffle(nums, n)
  result = []
  
  for i in (0..nums.size-n-1)
    result << nums[i]  
    result << nums[i+n]
  end
  result
end

bparanj

def pairs(nums)
  total = 0
  
  for i in (0..nums.size-2)
    for j in (i+1..nums.size-1)
      if nums[i] == nums[j]
        total += 1
      end
    end
  end