easyStringsPattern: Frequency Map
Character Frequency Counter Solution
Problem Statement
Given a string consisting of lowercase English letters, write a function to return a dictionary containing the frequency of each character in the string.
Examples
Example 1:
Input:hello
Output:{"h":1,"e":1,"l":2,"o":1}
Explanation: The character 'h' appears once, 'e' appears once, 'l' appears twice, and 'o' appears once in the input string 'hello'.
Example 2:
Input:abcabc
Output:{"a":2,"b":2,"c":2}
Explanation: All characters in the input string 'abcabc' appear twice.
Constraints
- The length of the input string will not exceed 10^5 characters.
- The input string will only contain lowercase English letters.
- The function should return a dictionary where the keys are characters and the values are their frequencies in the string.
Time: O(n) Space: O(n)
A more efficient approach is to use a single pass through the string, utilizing a dictionary to store character frequencies. This approach has a time complexity of O(n), where n is the length of the string, making it much more efficient for large inputs.
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