const flat = arr => [].concat.apply([], arr.map(a => Array.isArray(a) ? flat(a) : a));
// Or
const flat = arr => arr.reduce((a, b) => Array.isArray(b) ? [...a, ...flat(b)] : [...a, b], []);

// Or
// See the browser compatibility at https://caniuse.com/#feat=array-flat
const flat = arr => arr.flat();

// Example
flat(['cat', ['lion', 'tiger']]);   // ['cat', 'lion', 'tiger']

var invertTree = function(root) {
    const reverseNode = node => {
        if (node == null) {
            return null
        }
        reverseNode(node.left);
        reverseNode(node.right);
        let holdLeft = node.left;
        node.left = node.right;
        node.right = holdLeft;
        return node;
    }

    return reverseNode(root);
};

const jwt = require("jsonwebtoken");

const authToken = (req, res, next) => {
	const token = req.headers["x-auth-token"];

	try {
	req.user = jwt.verify(token, process.env.ACCESS_TOKEN_SECRET);

	next();
	} catch (err) {
	console.log(err.message);
	res.status(401).json({ msg: "Error authenticating token" });
	}
};

module.exports = authToken;

const express = require('express')
const app = express()
const port = 3000

app.get('/', (req, res) => {
  res.send('Hello World!')
})

app.listen(port, () => {
  console.log(`Example app listening on port ${port}`)
})

/**
 * @param {number[]} nums
 * @return {boolean}
 */
var containsDuplicate = function(nums) {
    return new Set(nums).size !== nums.length
};

//QM Helper by Leif Messinger
//Groups numbers by number of bits and shows their binary representations.
//To be used on x.com
const minterms = prompt("Enter your minterms separated by commas").split(",").map(x => parseInt(x.trim()));
const maxNumBits = minterms.reduce(function(a, b) {
	return Math.max(a, Math.log2(b));
});
const bitGroups = [];
for(let i = 0; i < maxNumBits; ++i){
	bitGroups.push([]);
}
for(const minterm of minterms){
	let outputString = (minterm+" ");
	//Count the bits
	let count = 0;
	for (var i = maxNumBits; i >= 0; --i) {
		if((minterm >> i) & 1){
			++count;
			outputString += "1";
		}else{
			outputString += "0";
		}
	}
	bitGroups[count].push(outputString);
}
document.body.textContent = "";
document.body.style.setProperty("white-space", "pre");
for(const group of bitGroups){
	for(const outputString of group){
		document.body.textContent += outputString + "\r\n";
	}
}