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Characters in a String

Certification: Basic Level Accuracy: 85.71% Submissions: 7 Points: 5

Write a Java program that counts the frequency of each character in a given string. Return a HashMap where keys are characters and values are their frequencies. Ignore spaces, and case is sensitive.

Example 1
    

  • Input: s = "Hello World"
    • 

  • Output: {H=1, e=1, l=3, o=2, W=1, r=1, d=1}
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  • Explanation:

      

    • Spaces ignored, counts reflect correct frequencies
      • 

    

    •
Example 2
    

  • Input: s = "programming"
    • 

  • Output: {p=1, r=1, o=1, g=2, a=1, m=2, i=1, n=1}
    •
Constraints
    

  • 1 ≤ s.length ≤ 10^5
    • 

  • Ignore space character, preserve case
    • 

  • Time Complexity: O(n)
    • 

  • Space Complexity: O(k), k = unique characters
    •
StringsCognizantDeloitte
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Hint
Solution

Solution Hints

    
  
  • Use a HashMap to store characters as keys and their frequencies as values.
    • 
  
  • Iterate through each character in the string.
    • 
  
  • Skip space characters.
    • 
  
  • For each non-space character, update its frequency in the HashMap.
    • 
  
  • Return the resulting HashMap.
    •

Steps to solve by this approach:

 Step 1: Create an empty HashMap to store character frequencies.

 Step 2: Iterate through each character in the input string.

 Step 3: Check if the current character is a space; if so, skip it.

 Step 4: If the character is not a space, add it to the map or update its count.

 Step 5: Use getOrDefault() to handle both new characters and updates efficiently.

 Step 6: Return the completed HashMap with all character frequencies.

 Step 7: The output will show each character and its frequency in the string.

Submitted Code :