HackerRank Python Tutorial Challenges Solutions

Problems can be found over the given link -
https://www.hackerrank.com/domains/miscellaneous/python-tutorials

Author: vineetpandey

Diff for: Basic calculator.py

@@ -0,0 +1,8 @@
+# Enter your code here. Read input from STDIN. Print output to STDOUT
+a = float(raw_input())
+b = float(raw_input())
+print "%0.2f"%(a+b)
+print "%0.2f"%(a-b)
+print "%0.2f"%(a*b)
+print "%0.2f"%(a/b)
+print "%0.2f"%(a//b)

Diff for: Class 1 - Dealing with complex numbers.py

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+# Enter your code here. Read input from STDIN. Print output to STDOUT
+# Author : Vineet
+
+import math
+
+class ComplexNo(object):
+    def __init__(self, real, imaginary):
+        self.real = real
+        self.imaginary = imaginary
+
+    def __add__(self, no):
+        real = self.real + no.real
+        imaginary = self.imaginary + no.imaginary
+        return ComplexNo(real, imaginary)
+
+    def __sub__(self, no):
+        real = self.real - no.real
+        imaginary = self.imaginary - no.imaginary
+        return ComplexNo(real, imaginary)
+
+    def __mul__(self, no):
+        real = self.real * no.real - self.imaginary * no.imaginary
+        imaginary = self.real * no.imaginary + self.imaginary * no.real
+        return ComplexNo(real, imaginary)
+
+    def __div__(self, no):
+        x = float(no.real ** 2 + no.imaginary ** 2)
+        y = self * ComplexNo(no.real, -no.imaginary)
+        real = y.real / x
+        imaginary = y.imaginary / x
+        return ComplexNo(real, imaginary)
+
+    def mod(self):
+        real = math.sqrt(self.real ** 2 + self.imaginary ** 2)
+        return ComplexNo(real, 0)
+# can also use __repr__ in place of __str__
+    def __str__(self):
+        if self.imaginary == 0:
+            result = "%.2f" % (self.real)
+        elif self.real == 0:
+            result = "%.2fi" % (self.imaginary)
+        elif self.imaginary > 0:
+            result = "%.2f + %.2fi" % (self.real, self.imaginary)
+        else:
+            result = "%.2f - %.2fi" % (self.real, abs(self.imaginary))
+        return result
+
+
+C = map(float, raw_input().split())
+D = map(float, raw_input().split())
+x = ComplexNo(*C)
+y = ComplexNo(*D)
+final = [x+y, x-y, x*y, x/y, x.mod(), y.mod()]
+print '\n'.join(map(str, final))

Diff for: Class 2 - Find the torsional angle.py

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+# Enter your code here. Read input from STDIN. Print output to STDOUT
+# Author : Vineet
+
+import math
+
+class Points(object):
+    def __init__(self, x, y, z):
+        self.x = x
+        self.y = y
+        self.z = z
+
+    def __sub__(self, no):
+        x = self.x - no.x
+        y = self.y - no.y
+        z = self.z - no.z
+        return Points(x, y, z)
+
+    def dot(self, no):
+        x = self.x * no.x
+        y = self.y * no.y
+        z = self.z * no.z
+        return x + y + z
+
+    def cross(self, no):
+        x = self.y * no.z - self.z * no.y
+        y = self.z * no.x - self.x * no.z
+        z = self.x * no.y - self.y * no.x
+        return Points(x, y, z)
+
+    def absolute_scale(self):
+        return pow((self.x ** 2 + self.y ** 2 + self.z ** 2), .5)
+
+
+def solve(A, B, C, D):
+    A, B, C, D = Points(*A), Points(*B), Points(*C), Points(*D)
+    X = (B - A).cross(C - B)
+    Y = (C - B).cross(D - C)
+    angle = math.acos(X.dot(Y) / (X.absolute_scale() * Y.absolute_scale()))
+    print "%.2f" % math.degrees(angle)
+
+points = list()
+for i in range(4):
+    a = map(float, raw_input().split())
+    points.append(a)
+solve(*points)

Diff for: Decorators 2 - Name directory.py

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+# Enter your code here. Read input from STDIN. Print output to STDOUT
+# Author : Vineet
+
+from operator import itemgetter
+from itertools import groupby
+
+N = int(raw_input())
+lst = list()
+for i in range(N):
+    a = raw_input()
+    lst.append(a.split())
+    
+lst.sort(key=itemgetter(2))
+
+for elt, items in groupby(lst, itemgetter(2)):
+    for i in items:
+        if i[3] == 'M':
+            print "Mr.",i[0],i[1]
+        else:
+            print "Ms.",i[0],i[1]

Diff for: Find a string.py

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+# Enter your code here. Read input from STDIN. Print output to STDOUT
+# Author : Vineet
+s1 = str(raw_input())
+s2 = str(raw_input())
+
+# print s1.count(s2) -- for non-overlapping sequences
+# Below is code for overlapping sequences
+cnt = 0
+for i in range(len(s1)):
+    if s1[i:].startswith(s2):
+		cnt += 1
+    #i += x
+print cnt

Diff for: Find second maximum number in a list.py

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+# Enter your code here. Read input from STDIN. Print output to STDOUT
+# Author : Vineet
+N = int(raw_input())
+x = raw_input()
+a1 = x.split()
+A = list(map(int, a1))
+x = max(A)
+k1 = list()
+for i in range(len(A)):
+	if x != A[i]:
+		k1.append(A[i])
+y = max(k1)
+print y

Diff for: Finding the percentage.py

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+# Enter your code here. Read input from STDIN. Print output to STDOUT
+# Author : Vineet
+N = int(raw_input())
+dc = dict()
+lst1 = list()
+for i in range(N):
+    a = raw_input()
+    lst1 = a.split()
+    d = lst1[0]
+    lst1.remove(lst1[0])
+    newlst1 = list(map(float, lst1))
+    dc[d] = newlst1
+name = raw_input()
+total = 0
+if name in dc:
+    marks = dc[name]
+    no = len(marks)
+    for num in marks:
+        total += num
+avg = total / no
+print "%.2f" % avg

Diff for: Info.txt

@@ -0,0 +1,4 @@
+
+Problems can be found over:
+
+https://www.hackerrank.com/domains/miscellaneous/python-tutorials

Diff for: Interchange two numbers.py

@@ -0,0 +1,10 @@
+# Enter your code here. Read input from STDIN. Print output to STDOUT
+a = raw_input()
+b = raw_input()
+x = a,
+y = b,
+z = y
+y = x
+x = z
+print x[0]
+print y[0]

Diff for: List Comprehensions.py

@@ -0,0 +1,11 @@
+# Enter your code here. Read input from STDIN. Print output to STDOUT
+
+#Input
+x = int(raw_input())
+y = int(raw_input())
+z = int(raw_input())
+N = int(raw_input())
+#Solve
+arr = [[X, Y, Z] for X in range(x+1) for Y in range(y+1) for Z in range(z+1) if X + Y + Z != N]
+#Output
+print(arr)

Diff for: Map and Lambda Function.py

@@ -0,0 +1,14 @@
+# Enter your code here. Read input from STDIN. Print output to STDOUT
+# Author : Vineet
+from itertools import islice 	# For making an iterator that returns selected elements from the iterable.
+n = abs(int(raw_input()))
+
+def fib(a=0, b=1):
+    yield a
+    while True:
+        yield b
+        a, b = b, a + b
+
+lst = list(islice(fib(), n))
+cube = lambda x: x * x * x
+print list(map(cube, lst))

Diff for: Nested list.py

@@ -0,0 +1,32 @@
+# Enter your code here. Read input from STDIN. Print output to STDOUT
+
+N = int(raw_input())
+final = list()
+for i in range(N):
+    lst = list()
+    name = str(raw_input())
+    marks = float(raw_input())
+    lst.append(name)
+    lst.append(marks)
+    final.append(lst)
+
+# print final
+# print len(final)
+k = list()
+for i in range(len(final)):
+    k.append(final[i][1])
+# print k
+x = min(k)
+k1 = list()
+for i in range(len(k)):
+	if x != k[i]:
+		k1.append(k[i])
+y = min(k1)
+# print x
+student = list()
+for i in range(len(final)):
+    if y == final[i][1]:
+        student.append(final[i][0])
+student.sort()
+for i in range(len(student)):
+    print student[i]

Diff for: Regex 1- Validating the phone number.py

@@ -0,0 +1,14 @@
+# Enter your code here. Read input from STDIN. Print output to STDOUT
+# Author : Vineet
+
+import re
+N = int(raw_input())
+number = [raw_input() for i in range(N)]
+check = lambda no:len(re.findall("^[7-9]\d{9}$",no))
+match = map(check, number)
+
+for i in match:
+    if i == 1:
+        print "YES"
+    else:
+        print "NO"

Diff for: Regex 2 - Validate a Roman Number.py

@@ -0,0 +1,10 @@
+# Enter your code here. Read input from STDIN. Print output to STDOUT
+# Author : Vineet
+
+import re
+pattern = '^(?=[MDCLXVI])M{0,3}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})$'
+roman = str(raw_input())
+if re.search(pattern, roman):
+    print 'True'
+else:
+    print 'False'

Diff for: Sets - Symmetric Difference.py

@@ -0,0 +1,33 @@
+# Enter your code here. Read input from STDIN. Print output to STDOUT
+#-------------------------------------------------------------------------------
+# Name:        module1
+# Purpose:
+#
+# Author:      Vineet
+#
+# Created:     05/12/2014
+# Copyright:   (c) Vineet 2014
+# Licence:     <your licence>
+#-------------------------------------------------------------------------------
+
+M = raw_input()
+a = raw_input()
+lst1 = a.split()
+newlst1 = list(map(int, lst1))
+set1 = set(newlst1)
+N = raw_input()
+b = raw_input()
+lst2 = b.split()
+newlst2 = list(map(int, lst2))
+set2 = set(newlst2)
+x = set1.difference(set2)
+#print x
+y = set2.difference(set1)
+#print y
+z = set()
+z = x.union(y)
+#print z
+lst = list(z)
+lst = sorted(lst)
+for i in range(len(lst)):
+    print lst[i]

Diff for: Standardize mobile number using Decorators.py

@@ -0,0 +1,18 @@
+# Enter your code here. Read input from STDIN. Print output to STDOUT
+# Author : Vineet
+
+number = list()
+N = int(raw_input())
+for i in range(N):
+    number.append(str(raw_input()))
+
+def mobile(function):
+    def input(number):
+            return sorted([function(i) for i in number])
+    return input
+
+@mobile
+def standardize(number):
+	return "+91" + " " + number[-10:-5] + " " + number[-5:]
+
+print '\n'.join(standardize(number))

Diff for: Validate list of email address with filter.py

@@ -0,0 +1,15 @@
+# Enter your code here. Read input from STDIN. Print output to STDOUT
+# Author : Vineet
+
+import re
+
+pattern = "^[a-zA-Z0-9-_]+@[a-zA-Z0-9]+\.[a-z]{1,3}$"
+
+N = int(raw_input())
+email = [ raw_input() for i in range(N) ]
+valid_email = list()
+for i in email:
+    if re.match(pattern,i):
+        valid_email.append(i)
+
+print sorted(valid_email)

Diff for: Whats your name!.py

@@ -0,0 +1,4 @@
+# Enter your code here. Read input from STDIN. Print output to STDOUT
+fn = raw_input()
+ln = raw_input()
+print "Hello %s %s! You just delved into python."%(fn,ln)

Diff for: XML 1 - Find the score.py

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+# Enter your code here. Read input from STDIN. Print output to STDOUT
+# Author : Vineet
+
+import xml.etree.ElementTree as etree
+
+N = int(raw_input())
+xml = ""
+for i in range(N):
+    xml += str(raw_input())
+
+tree = etree.ElementTree(etree.fromstring(xml))
+#root = tree.getroot()
+count = 0
+#count = len(root.attrib)
+for element in tree.iter():
+    count += len(element.attrib)
+print count