Check if the Sentence Is Pangram

Problem Summary

• A sentence is Pangram if all 26 letters of the alphabet is used at least once

Main Concepts Used

(Mark the CS concepts or algorithms used.)

• Sets
• Strings

Time & Space Complexity

• Time: $O(n)$ → Reason: Iterating through each letter in the sentence
• Space: $O(1)$ → Reason: Only storing upto 26 letters in the set

Code

class Solution:
    def checkIfPangram(self, sentence: str) -> bool:
        lettersSeen = set()
        for character in sentence:
            if character.isalpha():
                lettersSeen.add(character.lower())
        return len(lettersSeen) == 26