From 8a7579f2f57a16a592828974c02b590f5346512c Mon Sep 17 00:00:00 2001
From: jrtechs <jeffery@jrtechs.net>
Date: Fri, 12 Oct 2018 17:12:44 -0400
Subject: [PATCH] Added file which has two ways for doing quick sort.

---
 other/hasSum.py      | 49 ++++++++++++++++++++++++++++++++++
 recurrences.py       |  0
 sorting/quickSort.py | 63 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 112 insertions(+)
 create mode 100644 other/hasSum.py
 create mode 100644 recurrences.py
 create mode 100644 sorting/quickSort.py

diff --git a/other/hasSum.py b/other/hasSum.py
new file mode 100644
index 0000000..eed4dcf
--- /dev/null
+++ b/other/hasSum.py
@@ -0,0 +1,49 @@
+def sortedHasSum(s, x):
+    tempSum = 0
+    for i in range(len(s) -1, -1, -1):
+        if tempSum + s[i] <= x:
+            tempSum += s[i]
+        if(tempSum == x):
+            return True
+    return False
+
+
+def hasSumHelper(s, x):
+    if len(s) == 1:
+        if x - s[0] >= 0:
+            return x - s[0]
+        else:
+            return x
+    elif len(s) == 0:
+        return x;
+    lower,equal,upper = partition(s)
+
+    leftOver = hasSumHelper(upper, x)
+
+    if len(equal) > 1:
+        leftOver = hasSumHelper([equal[0]], leftOver)
+        leftOver = hasSumHelper(equal[1::],leftOver)
+    else:
+        leftOver = hasSumHelper(upper, leftOver)
+
+    return hasSumHelper(lower, leftOver)
+
+
+def hasSum(s, x):
+    return hasSumHelper(s, x) == 0
+
+
+def partition(data):
+    pivot = len(data) -1
+    lower, equal, upper = [], [], []
+
+    for i in range(0, len(data), 1):
+        if data[i] > data[pivot]:
+            upper.append(data[i])
+        elif data[i] == data[pivot]:
+            equal.append(data[i])
+        else:
+            lower.append(data[i])
+
+    return lower, equal, upper
+
diff --git a/recurrences.py b/recurrences.py
new file mode 100644
index 0000000..e69de29
diff --git a/sorting/quickSort.py b/sorting/quickSort.py
new file mode 100644
index 0000000..9ed48cc
--- /dev/null
+++ b/sorting/quickSort.py
@@ -0,0 +1,63 @@
+"""
+Jeffery Russell
+10-6-18
+
+File Containing Variations of Quick Sort
+"""
+
+
+def partition(data):
+    """
+    Partitions a list of data into three sections
+    which are lower, equal, and equal to the pivot
+    which is selected to be the last element in the
+    list.
+    """
+    pivot = len(data) -1
+    lower, equal, upper = [], [], []
+
+    for i in range(0, len(data), 1):
+        if data[i] > data[pivot]:
+            upper.append(data[i])
+        elif data[i] == data[pivot]:
+            equal.append(data[i])
+        else:
+            lower.append(data[i])
+
+    return lower, equal, upper
+
+
+def quickSortNormal(data):
+    """
+    This is the traditional implementation of quick sort
+    where there are two recursive calls.
+    """
+    if len(data) == 0:
+        return []
+    else:
+        less, equal, greater = partition(data)
+        return quickSortNormal(less) + equal + quickSortNormal(greater)
+
+
+def quick_sort_accumulation(data, a):
+    """
+    Implementation of quickSort which forces tail recursion
+    by wrapping the second recursive in the tail positioned
+    recursive call and added an accumulation variable.
+    """
+    if len(data) == 0:
+        return a
+    less, equal, greater = partition(data)
+    return quick_sort_accumulation(less,
+                                   equal + quick_sort_accumulation(greater, a))
+
+
+def quicksort(data):
+    """
+    Wrapper function for quick sort accumulation.
+    """
+    return quick_sort_accumulation(data, [])
+
+
+
+print quicksort([1,3,1,5,7,9,2,3,5,5,6])