# Node JS Template for Google Code Jam and Kick Start

**TLDR**: Here is the Node JS template for Google Code Jam and Kick Start: https://gitlab.com/snippets/1970354

- Copy-paste the code snippet into
`app.js`

- Copy your input into
`input.txt`

- Run
`node app.js < input.txt`

```
function readInput() {
const readline = require('readline')
const rl = readline.createInterface({
input: process.stdin,
output: process.stdout,
terminal: false
})
let problem = {
T: 0,
testCases: []
}
rl.on('line', function (line) {
// TODO: Process input
if (problem.T === 0) {
// Get number of test cases from first line
problem.T = Number(line)
} else {
// TODO process the rest of the data
const [a, b] = line.split(' ')
const aNum = Number(a)
const bNum = Number(b)
problem.testCases.push([aNum, bNum])
}
})
.on('close', () => {
// Finished processing input, now solve question
solveProblem(problem)
process.exit()
})
}
readInput()
```

Are you planning on trying out Google's coding competitions?

If it’s your first time, you might come across the same confusion that I did on my Google Code Jam.

That is, **how do you work with standard input and output on this platform**? It’s not like Leetcode where you simply need to define a function that takes in a pre-defined object.

## It’s not like Leetcode

Take a look at the following question:

Consider the following very simple problem. The input consists of one line with a number of test cases T, and then T more lines, each of which contains two positive integers N and M. The desired output form is Case #x: y z, where x, y, and z are all integers; x is the case number (starting from 1), y is the sum of N and M, and z is the product of N and M.

```
// input.txt
3
1 5
7 -2
9001 0
```

That’s it.

You aren’t given a template function. There isn’t a defined input object. You have a blank page and you just need to copy-paste the code that solves the problem on the page.

So how do you get started?

## Standard input and output

For those using Node JS, I recommend using Node’s readline.

You can define the standard input and output as follows:

```
const readline = require('readline')
const rl = readline.createInterface({
input: process.stdin,
output: process.stdout,
terminal: false
})
```

`readline`

has the following events.

- close
- line
- pause
- resume
- SIGCONT
- SIGINT
- SIGTSTP

The ones I used are **line** and **close**.

The basic idea is this:

```
rl.on('line', function (line) {
// process all of the given input, line by line
})
.on('close', () => {
// finished processing the input
// now we can solve the problem
}
```

Let’s go back to the given problem.

Consider the following very simple problem. The input consists of one line with a number of test cases T, and then T more lines, each of which contains two positive integers N and M. The desired output form is Case #x: y z, where x, y, and z are all integers; x is the case number (starting from 1), y is the sum of N and M, and z is the product of N and M.

```
// input.txt
3
1 5
7 -2
9001 0
```

We could process the input as follows:

```
let problem = {
T: 0,
testCases: []
}
rl.on('line', function (line) {
// Process input
if (problem.T === 0) {
problem.T = Number(line)
} else {
const [a, b] = line.split(' ')
const aNum = Number(a)
const bNum = Number(b)
problem.testCases.push([aNum, bNum])
}
})
.on('close', () => {
// Finished processing input, now solve question
solveProblem(problem)
process.exit()
})
```

Given the simplicity of the question, it may be easier to just solve the entire problem as you read in the input inside the `line`

event. But actual Code Jam questions are much more complicated, so I found it helpful to isolate the logic of reading the input from the problem-solving code.

## Testing it locally

Put both your JS code and `input.txt`

in the same folder.

Your directory structure should look something like this:

```
app.js
input.txt
```

If so, you can simply run `node app.js < input.txt`

on your terminal and your code will consume all the test cases inside `input.txt`

.

Hope this helps! Happy programming!