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+#!/usr/bin/env python3
+
+###########################################################################
+# script name: ch-1.py                                                    #
+#                                                                         #
+# https://github.com/user-person                                          #
+#                                                                         #
+# https://perlweeklychallenge.org/blog/perl-weekly-challenge-055/         #
+#                                                                         #
+# Flip Binary                                                             #
+#                                                                         #
+# You are given a binary number B, consisting of N binary digits          #
+# 0 or 1: s0,s1, ..., s(N-1).                                             #
+#                                                                         #
+# Choose two indices L and R such that 0 <= L <= R < N and flip the       #
+# digits s(L),s(L+1), ... , s(R) By flipping, we mean changing 0 to 1     #
+# and vice-versa.                                                         #
+#                                                                         #
+# Write a script to find the indices (L,R) that results in a              #
+# binary number with maximum number of 1s. If you find more than one      #
+# maximal pair L,R then print all of them.                                #
+#                                                                         #
+# Continuing our example, note that we had three pairs (L=0, R=0),        #
+# (L=0, R=2), and (L=2, R=2) that resulted in a binary number with        #
+# two 1s, which was the maximum. So we would print all three pairs.       #
+#                                                                         #
+###########################################################################
+
+import re
+import sys
+    
+originalString = "010"
+
+if len(sys.argv) > 1:
+    originalString = ''.join(sys.argv[1:])
+    if re.search(r'[^01]', str(originalString)):
+        sys.stderr.write('Arguments can only contain 1s and 0s.\n')
+        sys.exit(1)
+else:
+    sys.stderr.write('No arguments given. Using example data: 010\n')
+
+n = len(originalString)
+lowerBound = 0
+upperBound = n
+max = 0
+maxes = []
+
+hasZeroes = False
+if re.search(r'0', originalString):
+    hasZeroes = True
+
+if re.search(r'\A1+', originalString) and hasZeroes:
+    front = re.search(r'\A(1+)', originalString)
+    lowerBound = len(front.group(0))
+
+if re.search(r'1+\Z', originalString) and hasZeroes:
+    back = re.search(r'(1+)\Z', originalString)
+    difference = len(back.group(0))
+    upperBound = n - difference
+    
+left = lowerBound
+while left <= upperBound:
+    
+    right = left+1
+
+    while right <= upperBound:
+        binarySet = list(originalString)
+        for x in range(left,right,1):
+            if binarySet[x] == '0':
+                 binarySet[x] ='1'
+            elif binarySet[x] == '1':
+                binarySet[x] = '0'
+
+        num = binarySet.count('1')
+        
+        if num > max:
+            max = num
+            maxes = []
+            maxes.append('(L=%d, R=%d)' % (left, right-1))
+        elif num == max:
+            maxes.append('(L=%d, R=%d)' % (left, right-1))
+
+        right += 1
+    left += 1
+    
+for coord in maxes:
+    print(coord,end=' ')
+else:
+    print()