/*
Efficient algorithm using JavaScript Sets:
-----------------------------------------
Each word is converted into a Set of its unique letters.
Example:
"algebraic" -> Set { 'a', 'l', 'g', 'e', 'b', 'r', 'i', 'c' }
Then:
- Start with the set of letters from the first word.
- Intersect with each subsequent word's letter set.
- The final set contains letters common to all words.
This uses JavaScript's built-in:
- Set()
- for...of iteration
- functional decomposition
*/
// Convert a word into a Set of its unique letters
function lettersOf(word) {
return new Set(word);
}
// Compute letters common to all words
function commonLetters(words) {
if (words.length === 0) return new Set();
// Start with letters of the first word
let common = lettersOf(words[0]);
// Intersect with each subsequent word
for (let i = 1; i < words.length; i++) {
const current = lettersOf(words[i]);
common = new Set([...common].filter(ch => current.has(ch)));
}
return common;
}
// Print letters in sorted order
function printLetters(letters) {
console.log([...letters].sort().join(" "));
}
// Main program
const words = [
"algebraic",
"alphabetic",
"ambiance",
"abacus",
"metabolic",
"parabolic",
"playback",
"drawback",
"fabricate",
"flashback",
"syllabic"
];
const result = commonLetters(words);
console.log("Common letters across all words:");
printLetters(result);
/*
run:
Common letters across all words:
a b c
*/
