day 4 problems

day4_josephus_brute_force.py

@@ -0,0 +1,41 @@
+# Required concepts: https://www.w3schools.com/python/python_intro.asp strings
+
+print('Question: Shoot your neighbours, Josephus Problem')
+
+n = int(input('how many ppl stand in circle: '))
+
+kills = 0
+cur_gun_holder = 0
+to_shoot = -1
+dead = set()
+
+while cur_gun_holder != to_shoot:
+  # who to shoot? 
+  # whoever is alive and next to me!!!!
+  to_shoot = (cur_gun_holder+1)%n
+  while to_shoot in dead:
+    to_shoot = (to_shoot+1)%n
+  print(cur_gun_holder+1,'shoots',to_shoot+1)
+  if cur_gun_holder == to_shoot:
+    break
+  # now we kill him
+  dead.add(to_shoot)
+  kills += 1
+
+  # who gets the gun ?
+  # next alive guy
+  cur_gun_holder = (cur_gun_holder+1)%n
+  while cur_gun_holder in dead:
+    cur_gun_holder = (cur_gun_holder+1)%n
+
+print('Answer:')
+print(cur_gun_holder, 'is alive')
+
+"""
+# Superb Circular Linked List Solution!
+
+while node.next:
+
+  node.next = node.next.next # kill your next!
+  node = node.next # pass the gun
+"""

day4_max_product.py

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+# Required concepts: https://www.w3schools.com/python/python_intro.asp lists
+
+print('Question: Maximum product of two elements in array')
+
+
+
+li = [-7,-6,4,1,2,3,4,5,6]
+li.sort()
+# 5*6 or -7*-6 only those could give me the maximum
+# product of the two smallest, neg*neg 
+first = li[0]*li[1]
+last = li[-1]*li[-2]
+
+print('Answer:')
+print(max(first,last))

day4_print_rotations.py

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+# Required concepts: https://www.w3schools.com/python/python_intro.asp strings
+
+print('Question: Print all rotations of a list')
+
+# suboptimal is :
+#
+#for i in range(len(li)):
+#  print(li[-i:] + lst[:-i])
+
+
+# this is the optimal solution, without any extra space, since we are just printing!
+
+li = [1,2,3,4,5,6]
+n = len(li)
+# for each rotation you start at the new start
+for new_start in range(n):
+  next_ = (new_start + 1)%n
+  print('\n',li[new_start], end=' ')
+  while next_ != new_start:
+    print(li[next_],end=' ')
+    next_ = (next_+1)%n
+    # keep printing in circular fashion until you reach the start poiint :D
+
+
+print('\nare all rotations, our answer')
+
+
+
+

main.py

@@ -1,32 +1,20 @@
-# Required concepts: https://www.w3schools.com/python/python_intro.asp strings and slicing
+# Required concepts: https://www.w3schools.com/python/python_intro.asp lists
 
-print('Question: reverse each word of string')
+print('Question: Maximum product of two elements in array')
 
-sentence = 'hello world how are     you'
-res = ''
 
-for word in sentence.split():
-  # get each word from the split function
-  res += word[::-1]+" "
-  #add the reverse of it
+
+li = [-7,-6,4,1,2,3,4,5,6]
+li.sort()
+# 5*6 or -7*-6 only those could give me the maximum
+# product of the two smallest, neg*neg 
+first = li[0]*li[1]
+last = li[-1]*li[-2]
 
 print('Answer:')
-print(res)
-
-"""
-# what to reverse?
-# reverse upto the space
-left = 0
-while left < len(sentence):
-  right = sentence.find(' ',left)
-  if right == -1:
-    right = len(sentence)
-  word = sentence[left:right]
-  # now add this reversed word to result!
-  print(res)
-  res += word[::-1]
-  left = right
-  #now start from here
-"""
+print(max(first,last))
+
+
+