// sortByFrequency — counts how often each letter appears and returns a sorted list
function sortByFrequency(s) {
// Create a frequency array for 26 lowercase letters, initialized to 0
const freq = Array(26).fill(0);
// Iterate through the string and count only alphabetic characters
for (const c of s) {
if (/[a-zA-Z]/.test(c)) {
const idx = c.toLowerCase().charCodeAt(0) - 'a'.charCodeAt(0);
freq[idx]++;
}
}
// Build an array of {letter, freq} pairs
const result = [];
for (let i = 0; i < 26; i++) {
result.push({
letter: String.fromCharCode('a'.charCodeAt(0) + i),
freq: freq[i]
});
}
// Sort pairs by frequency in descending order
result.sort((a, b) => b.freq - a.freq);
return result;
}
// Build a string sorted by frequency: ddddddddddddccccccbbbbbaaaafffeehhgs
function buildSortedString(sorted) {
let out = "";
for (const p of sorted) {
// append 'p.letter' repeated p.freq times
if (p.freq > 0) {
out += p.letter.repeat(p.freq);
}
}
return out;
}
// Input text to analyze
const text = "bbcabddddccafffadbbcdccsedddddhhgade";
// Get sorted frequency list
const sorted = sortByFrequency(text);
// Print each letter and its frequency
for (const p of sorted) {
if (p.freq !== 0) {
console.log(`${p.letter}: ${p.freq}`);
}
}
// Print the reconstructed sorted string
const lettersSortedByFrequency = buildSortedString(sorted);
console.log("\nSorted string:", lettersSortedByFrequency);
/*
run:
d: 12
c: 6
b: 5
a: 4
f: 3
e: 2
h: 2
g: 1
s: 1
Sorted string: ddddddddddddccccccbbbbbaaaafffeehhgs
*/
