1 files changed, 107 insertions, 0 deletions
diff --git a/challenge-049/paulo-custodio/python/ch-2.py b/challenge-049/paulo-custodio/python/ch-2.py
new file mode 100644
index 0000000000..c299fc5530
--- /dev/null
+++ b/challenge-049/paulo-custodio/python/ch-2.py
@@ -0,0 +1,107 @@
+#!/usr/bin/env python3
+
+# Challenge 049
+#
+# TASK #2
+# LRU Cache
+# Write a script to demonstrate LRU Cache feature. It should support operations
+# get and set. Accept the capacity of the LRU Cache as command line argument.
+#
+# Definition of LRU: An access to an item is defined as a get or a set operation
+# of the item. "Least recently used" item is the one with the oldest access time.
+#
+# For example:
+#
+# capacity = 3
+# set(1, 3)
+# set(2, 5)
+# set(3, 7)
+#
+# Cache at this point:
+# [Least recently used] 1,2,3 [most recently used]
+#
+# get(2)      # returns 5
+#
+# Cache looks like now:
+# [Least recently used] 1,3,2 [most recently used]
+#
+# get(1)      # returns 3
+#
+# Cache looks like now:
+# [Least recently used] 3,2,1 [most recently used]
+#
+# get(4)      # returns -1
+#
+# Cache unchanged:
+# [Least recently used] 3,2,1 [most recently used]
+#
+# set(4, 9)
+#
+# Cache is full, so pushes out key = 3:
+# [Least recently used] 2,1,4 [most recently used]
+#
+# get(3)      # returns -1
+
+class Cache():
+    capacity = 0
+    cache = []
+
+    def __init__(self, capacity):
+        self.capacity = capacity
+        self.cache = []
+
+    def __str__(self):
+        out = ""
+        for x in self.cache:
+            out += "(" + str(x[0]) + "=>" + str(x[1]) + ")"
+        return out
+
+    def get(self, k):
+        for i in range(len(self.cache)):
+            if self.cache[i][0] == k:
+                v = self.cache[i][1]
+                self.cache = self.cache[0:i] + self.cache[i+1:]
+                self.cache.append([k,v])
+                return v
+        return -1
+
+    def set(self, k, v):
+        found = self.get(k)
+        if found == -1:
+            self.cache.append([k,v])
+            while len(self.cache) > self.capacity:
+                self.cache = self.cache[1:]
+        else:
+            self.cache[-1][1] = v
+
+print("Create cache, capacity=>3")
+cache = Cache(3)
+print("Cache="+str(cache))
+
+print("Set cache:1,3")
+cache.set(1, 3)
+print("Cache="+str(cache))
+
+print("Set cache:2,5")
+cache.set(2, 5)
+print("Cache="+str(cache))
+
+print("Set cache:3,7")
+cache.set(3, 7)
+print("Cache="+str(cache))
+
+print("Get cache 2=>"+str(cache.get(2)))
+print("Cache="+str(cache))
+
+print("Get cache 1=>"+str(cache.get(1)))
+print("Cache="+str(cache))
+
+print("Get cache 4=>"+str(cache.get(4)))
+print("Cache="+str(cache))
+
+print("Set cache:4,9")
+cache.set(4, 9)
+print("Cache="+str(cache))
+
+print("Get cache 3=>"+str(cache.get(3)))
+print("Cache="+str(cache))