Consonant Count - FreeCodeCamp #128 Daily Challenge

Consonant Count

1. Problem Statement

Given a string and a target number, determine if the string contains exactly that number of consonants.

• Consonants: all letters except a, e, i, o, u.
• Ignore digits, punctuation, spaces, and any non-alphabetic character.

2. Initial Analysis

What’s required? Count consonants in a string and compare to the target.

Test Cases

3. Solution & Code

Strategy:

1. Initialize a counter at 0.
2. Iterate each character:
   • Convert to lowercase.
   • Check if it’s a letter and not a vowel.
   • If it’s a consonant, add 1.
3. Compare the total to the target.

function hasConsonantCount(text, target) {
  let consonantCount = 0
  const vowels = 'aeiou'
  for (let char of text.toLowerCase()) {
    if (char >= 'a' && char <= 'z' && !vowels.includes(char)) {
      consonantCount++
    }
  }
  return consonantCount === target
}

Flowchart

flowchart TD
  A["Start"] --> B["Iterate each character"]
  B --> C{"Is it a letter and not a vowel?"}
  C -- Yes --> D["Add 1 to counter"]
  C -- No --> E["Ignore"]
  D --> F["Next character"]
  E --> F
  F --> G{"End of string?"}
  G -- No --> B
  G -- Yes --> H["Compare to target"]
  H --> I{"Match?"}
  I -- Yes --> J["Return true"]
  I -- No --> K["Return false"]

4. Complexity

• Time: $O(n)$, single pass through the string.
• Space: $O(1)$, only simple variables used.

5. Edge Cases

• Empty string → target 0
• Only vowels or only symbols → target 0
• Special characters and digits: ignored

6. Reflections

• Filtering for letters and vowels is key.
• The logic is simple and robust for strings of any size.
• Can be adapted to count vowels, letters, etc.