Adds various algorithm implementations including prefix sum, sliding window, and sorting algorithms

Author: shivabhusal

src/code/ruby/array/prefix_sum.rb

@@ -0,0 +1,13 @@
+# This method computes the prefix sum of an array.
+# It returns a new array where each element at index i is the sum of elements from index 0 to i-1 in the original array.
+# # For example, given the array [1, 2, 3], the prefix sum array will be [1, 3, 6].
+def prefix_sum(arr)
+  n       = arr.length
+  prefix  = [arr[0]]
+
+  (1...n).each do |i|
+    prefix << (prefix.last + arr[i])
+  end
+
+  prefix
+end

src/code/ruby/array/sliding_window.rb

@@ -0,0 +1,19 @@
+def fn(arr)
+  n       = arr.length
+  window  = 0
+  left    = 0
+  result  = 0
+
+  (0...n).each do |right|
+    # TODO: add arr[right] to window
+
+    while WINDOW_CONDITION_BROKEN
+      # TODO: remove arr[left] from window
+      left += 1
+    end
+
+    # TODO: update result
+  end
+
+  result
+end

src/code/ruby/array/string_building.rb

@@ -0,0 +1,15 @@
+def fn(strs)
+  # array of strings/chrs
+  ans = []
+
+  strs.each do |char|
+    ans << char
+  end
+
+  ans.join('')
+end
+
+# simple
+def fn2(strs)
+  strs.join
+end

src/code/ruby/array/two_pointers_one_input.rb

@@ -0,0 +1,16 @@
+def fn(arr)
+  ans   = 0
+  left  = 0
+  right = arr.length - 1
+
+  while left < right
+    # TODO: logic with left and right
+    if CONDITION
+      left  += 1
+    else
+      right -= 1
+    end
+  end
+
+  ans
+end

src/code/ruby/array/two_pointers_two_inputs.rb

@@ -0,0 +1,25 @@
+def fn(arr1, arr2)
+  i, j  = 0, 0
+  ans   = 0
+
+  while i < arr1.length && j < arr2.length
+    # TODO: Logic
+    if CONDITION
+      i += 1
+    else
+      j += 1
+    end
+  end
+
+  while i < arr1.length
+    # TODO: Logic
+    i += 1
+  end
+
+  while j < arr2.length
+    # TODO: Logic
+    j += 1
+  end
+
+  ans
+end

src/code/ruby/backtracking/backtracking.rb

@@ -0,0 +1,16 @@
+def backtrack(curr, OTHER_ARGUMENTS...)
+  if(BASE_CASE)
+    # TODO: modify answer
+    return
+  end
+
+  ans = 0
+
+  INPUTS.each do |i|
+    # TODO: modify current state
+    ans += backtrack(curr, OTHER_ARGUMENTS...)
+    # TODO: undo modification of current state
+  end
+
+  ans
+end

src/code/ruby/binary_search/binary_search.rb

@@ -0,0 +1,19 @@
+def fn(arr, target)
+  left  = 0
+  right = arr.length - 1
+
+  while left <= right
+    mid = (left + right) / 2
+
+    if arr[mid] == target
+      # TODO: logic
+      return
+    elsif arr[mid] > target
+      right = mid - 1
+    else
+      left = mid + 1
+    end
+  end
+
+  left
+end

src/code/ruby/binary_search/duplicate_elements_left_insertion.rb

@@ -0,0 +1,16 @@
+def fn(arr, target)
+  left  = 0
+  right = len(arr)
+
+  while left < right
+    mid = (left + right) / 2
+
+    if arr[mid] >= target
+      right = mid
+    else
+      left = mid + 1
+    end
+  end
+
+  left
+end

src/code/ruby/binary_search/duplicate_elements_right_insertion.rb

@@ -0,0 +1,16 @@
+def fn(arr, target)
+  left  = 0
+  right = len(arr)
+
+  while left < right
+    mid = (left + right) / 2
+
+    if arr[mid] > target
+      right = mid
+    else
+      left = mid + 1
+    end
+  end
+
+  left
+end

src/code/ruby/binary_search/greedy_maximum.rb

@@ -0,0 +1,21 @@
+def fn(arr)
+  left  = MINIMUM_POSSIBLE_ANSWER
+  right = MAXIMUM_POSSIBLE_ANSWER
+
+  while left <= right
+    mid = (left + right) / 2 # integer division
+
+    if check(mid)
+      left = mid + 1
+    else
+      right = mid - 1
+    end
+
+  end
+
+  right
+end
+
+def check(x)
+  BOOLEAN
+end