diff --git a/eating_cookies/eating_cookies.py b/eating_cookies/eating_cookies.py
index 62655d803..f79e9c0a8 100644
--- a/eating_cookies/eating_cookies.py
+++ b/eating_cookies/eating_cookies.py
@@ -5,8 +5,67 @@
 # The cache parameter is here for if you want to implement
 # a solution that is more efficient than the naive 
 # recursive solution
+# cache is the inventory --> 4 cookies
+# n is for cookies
+
 def eating_cookies(n, cache=None):
-  pass
+  # starter
+  # base:
+  if not cache:
+    cache = [0]*(n+1)
+  if n < 0:
+    return 0
+  elif n == 0:
+    return 1
+  elif cache[n] > 1:
+    return cache[n]
+  else:
+    cache[n] = eating_cookies(n-1, cache) + eating_cookies(n-2, cache) + eating_cookies(n-3, cache)
+    return cache[n]
+
+def eating_cookies2(n, cache=None):
+  # starter
+  # base:
+
+  if n <= 0:
+    return 0
+  if n == 1:
+    return 1
+  if n == 2:
+    return 2
+  if n == 3:
+    return 4
+
+  return eating_cookies2(n-1) + eating_cookies2(n-2) + eating_cookies2(n-3)
+# lines 41 and 42 debug eating cookies2 and it works on small numbers
+n=3
+print(eating_cookies2(n-1) + eating_cookies2(n-2) + eating_cookies2(n-3))
+
+def eating_cookies3(n, cache=None):
+  # starter
+  if cache is None:
+    cache = {}
+  # base:
+
+  if n <= 0:
+    return 0
+  elif n == 1:
+    return 1
+  elif n == 2:
+    return 2
+  elif n == 3:
+    return 4
+  elif cache and cache[n]:
+    return cache[n]
+  else:
+    cache[n] = eating_cookies3(n-1, cache) + eating_cookies3(n-2, cache) + eating_cookies3(n-3, cache)
+  
+
+  return cache[n]
+y = eating_cookies3(400, {})
+print(y)
+        
+
 
 if __name__ == "__main__":
   if len(sys.argv) > 1:
diff --git a/eating_cookies/improving.py b/eating_cookies/improving.py
new file mode 100644
index 000000000..6e566e69e
--- /dev/null
+++ b/eating_cookies/improving.py
@@ -0,0 +1,37 @@
+
+cache = {0: 1, 1: 1}
+def recursion_fibonacci(n):
+    #base
+    # if n == 0:
+    #     return 0
+    # if n == 1:
+    #     return 1
+
+    # handling cache
+    if n in cache:
+        return cache[n]
+    # if not in cache: 
+    cache[n] = recursion_fibonacci(n-1) + recursion_fibonacci(n-2)
+    return cache[n]
+
+x=recursion_fibonacci(10)
+print(x)
+# this log n which is reverse of exponential:
+nums = [1,2,3,4,5,6,7,8,9]
+def bin_search(arr, val):
+    l = 0
+    m = len(arr)//2
+    r = len(arr) - 1
+    while l < r:
+        if arr[m] == val:
+            return True
+        elif val < arr[m]:
+            # move left
+            return  m -1 
+        else:
+            # move right 
+            return m + 1
+    return False
+
+y = bin_search(nums, 5)
+print(y)  
diff --git a/knapsack/knapsack.py b/knapsack/knapsack.py
index a130284f1..ec28a12fa 100644
--- a/knapsack/knapsack.py
+++ b/knapsack/knapsack.py
@@ -5,9 +5,60 @@
 
 Item = namedtuple('Item', ['index', 'size', 'value'])
 
-def knapsack_solver(items, capacity):
-  pass
-  
+def knapsack_solver(capacity, items):
+ # "running capacities" from 0 up to and including the maximum weight W.
+  bestvalues = [[0] * (items + 1)
+          for i in range(len(capacity) + 1)]
+
+  # Enumerate through the items and fill in the best-value table
+  for i, (value, weight) in enumerate(capacity):
+    # Increment i, because the first row (0) is the case where no items
+    # are chosen, and is already initialized as 0, so we're skipping it
+    i += 1
+    for j in range(items + 1):
+      # Handle the case where the weight of the current item is greater
+      # than the "running capacity" - we can't add it to the knapsack
+      if weight > j:
+        bestvalues[i][items] = bestvalues[i - 1][items]
+      else:
+        # Otherwise, we must choose between two possible candidate values:
+        # 1) the value of "running capacity" as it stands with the last item
+        #    that was computed; if this is larger, then we skip the current item
+        # 2) the value of the current item plus the value of a previously computed
+        #    set of items, constrained by the amount of capacity that would be left
+        #    in the knapsack (running capacity - item's weight)
+        candidate1 = bestvalues[i - 1][j]
+        candidate2 = bestvalues[i - 1][j - weight] + value
+
+        # Just take the maximum of the two candidates; by doing this, we are
+        # in effect "setting in stone" the best value so far for a particular
+        # prefix of the items, and for a particular "prefix" of knapsack capacities
+        bestvalues[i][j] = max(candidate1, candidate2)
+
+    # Reconstruction
+    # Iterate through the values table, and check
+    # to see which of the two candidates were chosen. We can do this by simply
+    # checking if the value is the same as the value of the previous row. If so, then
+    # we say that the item was not included in the knapsack (this is how we arbitrarily
+    # break ties) and simply move the pointer to the previous row. Otherwise, we add
+    # the item to the reconstruction list and subtract the item's weight from the
+    # remaining capacity of the knapsack. Once we reach row 0, we're done
+  reconstruction = []
+  i = len(capacity)
+  z = items
+  while i > 0:
+    if bestvalues[i][z] != bestvalues[i - 1][z]:
+      reconstruction.append(items[i - 1])
+      z -= items[i - 1][1]
+      i -= 1
+
+  # Reverse the reconstruction list, so that it is presented
+  # in the order that it was given
+  reconstruction.reverse()
+
+  # Return the best value, and the reconstruction list
+  return bestvalues[len(capacity)][items], reconstruction
+
 
 if __name__ == '__main__':
   if len(sys.argv) > 1:
diff --git a/making_change/making_change.py b/making_change/making_change.py
index 9adad4470..a7730a185 100644
--- a/making_change/making_change.py
+++ b/making_change/making_change.py
@@ -3,7 +3,14 @@
 import sys
 
 def making_change(amount, denominations):
-  pass 
+  cache = [0 for i in range(amount + 1)]
+  cache[0] = 1
+  
+  for d in denominations:
+    for amount in range(d, amount +1): 
+      cache[amount] = cache[amount] + cache[amount - d]
+  
+  return cache[amount]
 
 
 if __name__ == "__main__":
diff --git a/recipe_batches/recipe_batches.py b/recipe_batches/recipe_batches.py
index c845950c5..8f081c12f 100644
--- a/recipe_batches/recipe_batches.py
+++ b/recipe_batches/recipe_batches.py
@@ -3,7 +3,15 @@
 import math
 
 def recipe_batches(recipe, ingredients):
-  pass 
+  # start
+  new_ingredients_for_item = [0]*len(recipe)
+  counter = 0 
+  #base
+  for i in recipe:
+    if i in ingredients:
+      new_ingredients_for_item[counter] = int(ingredients[i]/recipe[i])
+      counter += 1
+  return min(new_ingredients_for_item)
 
 
 if __name__ == '__main__':
diff --git a/rock_paper_scissors/rps.py b/rock_paper_scissors/rps.py
index 0fc53356e..eaa27a07f 100644
--- a/rock_paper_scissors/rps.py
+++ b/rock_paper_scissors/rps.py
@@ -3,8 +3,20 @@
 import sys
 
 def rock_paper_scissors(n):
-  pass 
+  #start
+  choices =  ['rock', 'paper', 'scissors']
+  possible_plays = []
 
+  #base 
+  def rps_helper_fun(result, num_plays):
+        # this should stop the recursion if there are no plays
+    if num_plays == 0:
+      possible_plays.append(result)
+      return
+    for i in range(0, len(choices)):
+      rps_helper_fun(result + [choices[i]], num_plays -1)
+  rps_helper_fun([], n)
+  return possible_plays
 
 if __name__ == "__main__":
   if len(sys.argv) > 1:
diff --git a/stock_prices/stock_prices.py b/stock_prices/stock_prices.py
index 9de20bc94..d5dd19021 100644
--- a/stock_prices/stock_prices.py
+++ b/stock_prices/stock_prices.py
@@ -3,9 +3,18 @@
 import argparse
 
 def find_max_profit(prices):
-  pass
 
+  current_min_price = prices[0]
+  max_profit = prices[1] - current_min_price
 
+  for i in range(len(prices)):
+    for j in range(i + 1, len(prices)):
+      if prices[j] - prices[i] > max_profit:
+        max_profit = prices[j] - prices[i]
+  return max_profit
+      
+            
+            
 if __name__ == '__main__':
   # This is just some code to accept inputs from the command line
   parser = argparse.ArgumentParser(description='Find max profit from prices.')