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breadth first values

Write a function, breadthFirstValues, that takes in the root of a binary tree. The function should return an array containing all values of the tree in breadth-first order.

const a = new Node('a');
const b = new Node('b');
const c = new Node('c');
const d = new Node('d');
const e = new Node('e');
const f = new Node('f');

a.left = b;
a.right = c;
b.left = d;
b.right = e;
c.right = f;

//      a
//    /   \
//   b     c
//  / \     \
// d   e     f

breadthFirstValues(a); 
//    -> ['a', 'b', 'c', 'd', 'e', 'f']

const a = new Node('a');
const b = new Node('b');
const c = new Node('c');
const d = new Node('d');
const e = new Node('e');
const f = new Node('f');
const g = new Node('g');
const h = new Node('h');

a.left = b;
a.right = c;
b.left = d;
b.right = e;
c.right = f;
e.left = g;
f.right = h;

//      a
//    /   \
//   b     c
//  / \     \
// d   e     f
//    /       \
//   g         h

breadthFirstValues(a); 
//   -> ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']

const a = new Node('a');

//      a

breadthFirstValues(a); 
//    -> ['a']

const a = new Node('a');
const b = new Node('b');
const c = new Node('c');
const d = new Node('d');
const e = new Node('e');
const x = new Node('x');

a.right = b;
b.left = c;
c.left = x;
c.right = d;
d.right = e;

//      a
//       \
//        b
//       /
//      c
//    /  \
//   x    d
//         \
//          e

breadthFirstValues(a); 
//    -> ['a', 'b', 'c', 'x', 'd', 'e']

breadthFirstValues(null); 
//    -> []

editor — breadth-first-values.js

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