sparseArrays.js

# source: https://www.hackerrank.com/challenges/sparse-arrays/problem
# Glitched Failure video: https://youtu.be/n9w7Nuy-FmA

function matchingStrings(strings, queries) {
    const memory = {};
    
    // O(n), where n = number of string
    for(const string of strings) memory[string] = (memory[string] || 0) + 1;

    // O(m), where m = number of queries (the lookup is constant time, O(1))
    return queries.map(query=> memory[query] || 0);
    
    // Total Time Complexity = O(n) + O(m) => O(n + m)
}