diff --git a/interview_cake/data_structures/angry_bird.py b/interview_cake/data_structures/angry_bird.py
new file mode 100644
index 0000000..13959f5
--- /dev/null
+++ b/interview_cake/data_structures/angry_bird.py
@@ -0,0 +1,37 @@
+#!/bin/python
+
+"""
+Each round, players receive a score between 0 and 100, which you use to rank them from highest to lowest. So far you're using an algorithm that sorts in O(n\lg{n})O(nlgn) time, but players are complaining that their rankings aren't updated fast enough. You need a faster sorting algorithm.
+
+Write a function that takes:
+
+a list of unsorted_scores
+the highest_possible_score in the game
+and returns a sorted list of scores in less than O(n\lg{n})O(nlgn) time.
+"""
+
+def sort_scores(unsorted_scores, highest_score):
+
+    score_counts = [0] * (highest_score+1)
+
+    for score in unsorted_scores:
+        score_counts[score] += 1
+
+    sorted_scores = []
+
+    for score in range(len(score_counts)-1, -1, -1):
+        count = score_counts[score]
+
+        for i in range(count):
+            sorted_scores.append(score)
+
+    return sorted_scores
+
+
+
+if __name__ == '__main__': 
+
+    unsorted_scores = [37, 89, 41, 65, 91, 53]
+    HIGHEST_POSSIBLE_SCORE = 100
+
+    print sort_scores(unsorted_scores, HIGHEST_POSSIBLE_SCORE)
diff --git a/interview_cake/data_structures/inflight_entrain.py b/interview_cake/data_structures/inflight_entrain.py
new file mode 100644
index 0000000..6862d70
--- /dev/null
+++ b/interview_cake/data_structures/inflight_entrain.py
@@ -0,0 +1,42 @@
+#!/bin/python
+
+"""
+Users on longer flights like to start a second movie right when their first one ends, 
+but they complain that the plane usually lands before they can see the ending. 
+So you're building a feature for choosing two movies whose total runtimes will equal the exact flight length.
+
+Write a function that takes an integer flight_length (in minutes) and a 
+list of integers movie_lengths (in minutes) and returns a boolean indicating 
+whether there are two numbers in movie_lengths whose sum equals flight_length.
+
+When building your function:
+
+Assume your users will watch exactly two movies
+Don't make your users watch the same movie twice
+Optimize for runtime over memory
+"""
+
+def is_there_two_movies(flight_length, movie_lengths):
+    movie_lengths_seen = set()
+
+    for first_movie_length in movie_lengths:
+        matching_second_movie_length = flight_length - first_movie_length
+        if matching_second_movie_length in movie_lengths_seen:
+            return True
+        movie_lengths_seen.add(first_movie_length)
+
+    return False
+
+
+
+if __name__ == '__main__':
+
+    flight_length = 10
+
+    movie_lengths = [2, 4, 7]
+    print(is_there_two_movies(flight_length, movie_lengths))
+    print("Should be True")
+
+    movie_lengths = [5, 6, 7, 8]
+    print(is_there_two_movies(flight_length, movie_lengths))
+    print("Should be False")
\ No newline at end of file
diff --git a/interview_cake/strings/online_poker.py b/interview_cake/strings/online_poker.py
new file mode 100644
index 0000000..d5c1aa8
--- /dev/null
+++ b/interview_cake/strings/online_poker.py
@@ -0,0 +1,28 @@
+#!/bin/python
+
+"""
+Write a function to tell us if a full deck of cards shuffled_deck is a single riffle of two other halves half1 and half2.
+
+We'll represent a stack of cards as a list of integers in the range 1..521..52 (since there are 5252 distinct cards in a deck).
+Why do I care? A single riffle is not a completely random shuffle. If I'm right, I can make more informed bets and get rich and finally prove to my ex that I am not a "loser with an unhealthy cake obsession" (even though it's too late now because she let me go and she's never getting me back).
+"""
+
+def is_single_riffle(half1, half2, shuffled_deck,
+                     shuffled_deck_index=0, half1_index=0, half2_index=0):
+    if shuffled_deck_index == len(shuffled_deck):
+        return True
+
+    if ((half1_index < len(half1)) and
+            half1[half1_index] == shuffled_deck[shuffled_deck_index]):
+        half1_index += 1
+
+    elif ((half2_index < len(half2)) and
+            half2[half2_index] == shuffled_deck[shuffled_deck_index]):
+        half2_index += 1
+    else:
+        return False
+
+    shuffled_deck_index += 1
+    return is_single_riffle(
+        half1, half2, shuffled_deck, shuffled_deck_index,
+        half1_index, half2_index)
\ No newline at end of file