Given a list of strings dict
where all the strings are the same length.
Return true
if there are two strings that only differ by one character in the same index, otherwise return false
.
Example 1:
Input: dict = ["abcd","acbd","aacd"]
Output: true
Explanation:
Strings "abcd" and "aacd" differ only by one character in the index 1.
Example 2:
Input: dict = ["ab","cd","yz"]
Output: false
Example 3:
Input: dict = ["abcd","cccc","abyd","abab"]
Output: true
Constraints:
1 <= dict.length <= 104
1 <= dict[i].length <= 100
dict[i]
consists of lowercase English letters.dict
have the same length.When you get asked this question in a real-life environment, it will often be ambiguous (especially at FAANG). Make sure to ask these questions in that case:
The brute force approach to finding if strings differ by one character is to compare each string against every other string in the list. We will look at all possible pairs of strings and check how many characters are different between them.
Here's how the algorithm would work step-by-step:
def strings_differ_by_one_character(input_strings):
for first_word_index in range(len(input_strings)):
first_word = input_strings[first_word_index]
# Compare the first word with the remaining words
for second_word_index in range(first_word_index + 1, len(input_strings)):
second_word = input_strings[second_word_index]
# Ensure words are of the same length for comparison
if len(first_word) != len(second_word):
continue
difference_count = 0
for char_index in range(len(first_word)):
if first_word[char_index] != second_word[char_index]:
difference_count += 1
# Check if the words differ by exactly one character
if difference_count == 1:
return True
# No pair of words differs by exactly one character
return False
The optimal approach involves systematically comparing each word with every other word to quickly identify if they differ by only one character. We use a trick to make these comparisons very efficient by focusing on potential differences rather than checking every character in every word.
Here's how the algorithm would work step-by-step:
def strings_differ_by_one_character(input_strings):
altered_strings_map = {}
for original_string in input_strings:
for index in range(len(original_string)):
# Create the altered string by removing one char
altered_string = original_string[:index] + original_string[index+1:]
# Store the altered string and its origin.
if altered_string in altered_strings_map:
if original_string not in altered_strings_map[altered_string]:
#Strings differ by one character if present
return True
else:
altered_strings_map[altered_string] = [original_string]
# No differing strings found.
return False
Case | How to Handle |
---|---|
strs is null or empty | Return false if strs is null or empty, as there are no strings to compare. |
strs contains fewer than 2 strings | Return false if strs contains fewer than 2 strings, as no comparison is possible. |
Strings in strs have different lengths | Return false or throw an exception, as strings must have the same length for a valid comparison. |
strs contains only identical strings | Return false if all strings in strs are identical, as they don't differ by any character. |
strs contains very long strings (performance) | Ensure that the chosen algorithm (e.g., hashing with wildcards) has reasonable time complexity for long strings to avoid timeouts. |
Large input array strs (memory considerations) | The solution should be memory-efficient, avoiding unnecessary copying or storing of large substrings; consider using iterators instead. |
Strings contain non-ASCII or Unicode characters | Ensure the character comparison logic is Unicode-aware if the strings might contain non-ASCII characters. |
Strings with only one character | Handle appropriately, comparing single character strings for difference is a valid scenario |