Problem Statement
Count Approach
class Solution:
def minimumLength(self, s: str) -> int:
counter = Counter(s)
res = 0
for c, count in counter.items():
while count >= 3:
count -= 2
res += count
return res
Editorial
Approach 1: Using Hash Map
class Solution:
def minimumLength(self, s: str) -> int:
# Step 1: Count the frequency of each character in the string
char_frequency_map = Counter(s)
# Step 2: Calculate the number of characters to delete
delete_count = 0
for frequency in char_frequency_map.values():
if frequency % 2 == 1:
# If frequency is odd, delete all except one
delete_count += frequency - 1
else:
# If frequency is even, delete all except two
delete_count += frequency - 2
# Step 3: Return the minimum length after deletions
return len(s) - delete_count
Approach 2: Using Frequency Array
class Solution:
def minimumLength(self, s: str) -> int:
# Step 1: Initialize a frequency array to count occurrences of each character
char_frequency = [0] * 26
total_length = 0
# Step 2: Count the frequency of each character in the string
for current_char in s:
char_frequency[ord(current_char) - ord("a")] += 1
# Step 3: Calculate the total length after deletions count
for frequency in char_frequency:
if frequency == 0:
continue # Skip characters that don't appear
if frequency % 2 == 0:
total_length += 2 # If frequency is even, add 2 characters
else:
total_length += 1 # If frequency is odd, add 1 character
# Step 4: Return the minimum length after deletions count
return total_length
