Add Python solution to challenge 059

2 files changed, 156 insertions, 0 deletions

diff --git a/challenge-059/paulo-custodio/python/ch-1.py b/challenge-059/paulo-custodio/python/ch-1.py
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+++ b/challenge-059/paulo-custodio/python/ch-1.py
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+#!/usr/bin/env python3
+
+# Challenge 059
+#
+# TASK #1 › Linked List
+# Reviewed by Ryan Thompson
+# You are given a linked list and a value k. Write a script to partition the
+# linked list such that all nodes less than k come before nodes greater than or
+# equal to k. Make sure you preserve the original relative order of the nodes in
+# each of the two partitions.
+#
+# For example:
+#
+# Linked List: 1 -> 4 -> 3 -> 2 -> 5 -> 2
+#
+# k = 3
+#
+# Expected Output: 1 -> 2 -> 2 -> 4 -> 3 -> 5.
+
+import sys
+
+class Node:
+    def __init__(self, data):
+        self.data = data
+        self.next = None
+
+    def __str__(self):
+        out = "["+str(self.data)
+        if self.next:
+            return out+","+str(self.next)+"]"
+        else:
+            return out+"]"
+
+class LinkedList:
+    def __init__(self):
+        self.head = None
+
+    def __str__(self):
+        out = ""
+        current = self.head
+        while current:
+            out += str(current.data)+" -> "
+            current = current.next
+        out += "None"
+        return out
+
+    def push_front(self, data):
+        new_node = Node(data)
+        new_node.next = self.head
+        self.head = new_node
+
+    def push_back(self, data):
+        new_node = Node(data)
+        if not self.head:
+            self.head = new_node
+        else:
+            last_node = self.head
+            while last_node.next:
+                last_node = last_node.next
+            last_node.next = new_node
+
+    def insert_at(self, index, data):
+        if index == 0:
+            self.push_front(data)
+        else:
+            new_node = Node(data)
+            current = self.head
+            for _ in range(index - 1):
+                if not current:
+                    raise IndexError("Index out of bounds")
+                current = current.next
+            new_node.next = current.next
+            current.next = new_node
+
+    def remove_node(self, key):
+        current = self.head
+        if current and current.data == key:
+            self.head = current.next
+            current = None
+        else:
+            prev = None
+            while current and current.data != key:
+                prev = current
+                current = current.next
+            if current:
+                prev.next = current.next
+                current = None
+
+def partition(list, k):
+    below = LinkedList()
+    above = LinkedList()
+
+    p = list.head
+    while p:
+        if p.data < k:
+            below.push_back(p.data)
+        else:
+            above.push_back(p.data)
+        p = p.next
+
+    list = below
+    p = above.head
+    while p:
+        list.push_back(p.data)
+        p = p.next
+
+    return list
+
+k = int(sys.argv[1])
+list = LinkedList()
+for x in sys.argv[2:]:
+    list.push_back(int(x))
+list = partition(list, k)
+print(list)
diff --git a/challenge-059/paulo-custodio/python/ch-2.py b/challenge-059/paulo-custodio/python/ch-2.py
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+++ b/challenge-059/paulo-custodio/python/ch-2.py
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+#!/usr/bin/env python3
+
+# Challenge 059
+#
+# TASK #2 > Bit Sum
+# Reviewed by Ryan Thompson
+# Helper Function
+# For this task, you will most likely need a function f(a,b) which returns the
+# count of different bits of binary representation of a and b.
+#
+# For example, f(1,3) = 1, since:
+#
+# Binary representation of 1 = 01
+#
+# Binary representation of 3 = 11
+#
+# There is only 1 different bit. Therefore the subroutine should return 1. Note
+# that if one number is longer than the other in binary, the most significant
+# bits of the smaller number are padded (i.e., they are assumed to be zeroes).
+#
+# Script Output
+# You script should accept n positive numbers. Your script should sum the result
+# of f(a,b) for every pair of numbers given:
+#
+# For example, given 2, 3, 4, the output would be 6,
+# since f(2,3) + f(2,4) + f(3,4) = 1 + 2 + 3 = 6
+
+import sys
+from itertools import combinations
+
+def f(a, b):
+    r = int(a) ^ int(b)
+    rt = bin(r)
+    return rt.count('1')
+
+n = list(map(int, sys.argv[1:]))
+sum_ = 0
+
+for combin in combinations(n, 2):
+    sum_ += f(combin[0], combin[1])
+
+print(sum_)