As part of my life now as a job seeker, I spend some time practicing challenges that will help me to improve my problem-solving skills. I use different sites to practice: Codewars, Hackerrank, Codility, Leetcode, and freeCodeCamp! These early morning I decided to do some of the challenges under the JS section of freeCodeCamp!! One of the funnest ones was to solve a DNA coding challenge!
Here is the challenge:
The DNA strand is missing the pairing element. Take each character, get its pair, and return the results as a 2d array.
Base pairs are a pair of AT and CG. Match the missing element to the provided character.
Return the provided character as the first element in each array.
For example, for the input GCG, return [[“G”, “C”], [“C”,”G”],[“G”, “C”]]
The character and its pair are paired up in an array, and all the arrays are grouped into one encapsulating array.
After some digging I ended up with this info:
G element will return [”G”, “C”]
C element will return [“C”, “G”]
A element will return [“A”, “T”]
T element will return [“T”, “A”]
The fun part begins now!! I always try to pseudo-code, it helps me to understand the problem and to organized my thoughts!
Pseudo-code:
- Create an empty array to store the pairs!
- A switch case would be useful to check for every element and push into the new array
- Loop through the elements to pair the strand(using the switch case)!
``` function pairElement(str) {
let strand = [];
const check = function(char) {
switch (char) {
case 'A':
strand.push(['A', 'T']);
break;
case 'G':
strand.push(['G', 'C']);
break;
case 'C':
strand.push(['C', 'G']);
break;
case 'T':
strand.push(['T', 'A']);
break;
}
};
for (let i = 0; i < str.length; i++) {
check(str[i]);
}
return strand; } ```
Time to test!! ✨✨🎊😎
Awesome!! It works!!