one array solution

concepts/1_arrays_and_strings/one_array/README.md

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+# Description
+3 Things can be done to a sting in this problem:
+1. insert character
+2. remove character
+3. replace character
+Given 2 strings, write a function that checks if they are one edit or zero edits away
+
+# Test Cases
+pale, pal (true) - remove one
+pales, pale (true) - add one
+pale, bale (true) - change one
+pale, bake (false) - two steps away
+
+# Thought Process
+1. Check for all 3 cases
+2. Check for amount of instances of each case
+3. Consider edge case - only having one character
+4. Does uppercase count? - no
+5. Do spaces count? - no
+6. Can we check for both insert and remove at the same time? - probably yes
+7. Can you check for all 3 at the same time? - probably yes
+8. Do a separate check for 0 edits away
+9. Thought of this case later: removing a char from the beginning of string

concepts/1_arrays_and_strings/one_array/one_array.py

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+import time
+import os.path
+
+# timer for speed testing of program logic
+def run_timer():
+	tests = 30
+	start_time = time.time() # start
+	for i in xrange(tests):
+		run_tests()
+	end_time = time.time()
+	total_time = (end_time - start_time) / tests # end
+	print("Runtime: %.10f seconds" % total_time)
+	# save results
+	file_name = "speed.csv"
+	if os.path.isfile(file_name) is False:
+		with open(file_name, "a") as results:
+			results.write("time,tests\n")
+	with open(file_name, "a") as results:
+		results.write("%.10f" % total_time)
+		results.write(",%s\n" % tests)
+
+# program logic
+def base(old,new):
+	if old == new:
+		return 'true'
+
+	found = 'false'
+	len1 = len(old)
+	len2 = len(new)
+	diff = len1 - len2
+	first = 'false'
+	second = 'false'
+
+	# check lengths
+	if abs( diff ) > 1: # break out early if leg diff is 2 or more
+		return 'false'
+	elif len1 > len2: # first string is longer
+		first = 'true'
+	elif len1 < len2: # second string is longer
+		second = 'true'
+
+	i1 = 0
+	i2 = 0
+	while i1 < len1 and i2 < len2:
+		if old[i1] != new[i2]: # could be spacing or char difference
+			if found == 'true':
+				return 'false'
+			found = 'true'
+
+			# move longer string up by 1
+			if first == 'true': # first is longer
+				i1 += 1
+				pass
+			elif second == 'true': # second is longer
+				i2 += 1
+				pass
+
+		i1 += 1
+		i2 += 1
+
+	return 'true'
+
+# test cases
+def run_tests():
+	print base('pale','pale') # true - 0 edits away
+	print base('pale','pal') # true - add one
+	print base('pales','pale') # true - remove one
+	print base('pale','bale') # true - change one
+	print base('pale','bake') # false - two steps away
+	print base('bbake','bake') # true - remove one
+
+# run_tests()
+run_timer()

concepts/1_arrays_and_strings/one_array/speed.csv

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+time,tests
+0.0000138998,30
+0.0000143369,30
+0.0000136296,30