Coding problem · Easy · Basics

Is It a Pangram?

Easy Algorithms & data structures

A pangram contains every letter from a to z at least once (case doesn't matter; other characters are ignored). Return true if s is a pangram.

Example 1

Input: s = "The quick brown fox jumps over the lazy dog"
Output: true

Example 2

Input: s = "Hello world"
Output: false

Hints

Hint 1

Collect the distinct letters you see in a set.

Hint 2

It's a pangram when the set holds 26 letters.

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Solution and explanation

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Time O(n) · Space O(1)

Add each lower-cased letter to a set and compare its size with 26. Ignore spaces and punctuation.

Reference solution

function isPangram(s) {
  const letters = new Set(s.toLowerCase().replace(/[^a-z]/g, ''));
  return letters.size === 26;
}

function isPangram(s: string): boolean {
  const letters = new Set(s.toLowerCase().replace(/[^a-z]/g, ''));
  return letters.size === 26;
}

def is_pangram(s: str) -> bool:
    return len({ch for ch in s.lower() if 'a' <= ch <= 'z'}) == 26

<?php

function isPangram(string $s): bool
{
    return count(array_unique(str_split(preg_replace('/[^a-z]/', '', strtolower($s)) ?: ' '))) === 26;
}

class Solution {
    public boolean isPangram(String s) {
        java.util.Set<Character> seen = new java.util.HashSet<>();
        for (char ch : s.toLowerCase().toCharArray()) if (ch >= 'a' && ch <= 'z') seen.add(ch);
        return seen.size() == 26;
    }
}

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