Mastery Points
0
Character Frequency maps in dsa
Context & Logic
Character frequency involves counting how many times each character appears in a string. This is usually done using a Hash Map or an object in JavaScript.
Example
function getFrequency(str) {
const freq = {};
for (let char of str) {
freq[char] = (freq[char] || 0) + 1;
}
return freq;
}
// getFrequency("hello") -> { h: 1, e: 1, l: 2, o: 1 }Step-by-Step Logic
1
Initialize an empty frequency object.
2
Loop through each character of the string.
3
Check if the character exists as a key in the object.
4
If it exists, increment its value; if not, initialize it to 1.
Complexity Metrics
Time Efficiency
O(n)
Memory Footprint
O(k) where k is the character set size