is_balanced

is_tree_balanced.js

log = console.log
function node(name, parent, child) {
 
    var new_node = { name:name, parent:parent }
    
    if (!!child) {
        new_node.parent[child] = new_node;
    }
 
    return new_node
}
 
/*
                root
            rl          rr
        rl2                 rr2
    rl3                         rr3
 
*/
root = node('root')
 
rl = node('rl', root, 'left')
rl2 = node('rl2', rl, 'left')
rl3 = node('rl3', rl2, 'left')
 
 
rr = node('rr', root, 'right')
rr2 = node('rr2', rr, 'right')
rr3 = node('rr3', rr2, 'right')

 
rlr = node('rlr', rl, 'right') //balances tree
rrl = node('rrl', rr, 'left') //balances tree

 
function height(nodz) {
    return (!nodz) ? 0 : 1 + Math.max(height(nodz.left), height(nodz.right));
}
 
function isBalanced(nodz) {
    return ((!nodz) || isBalanced(nodz.left) && isBalanced(nodz.right) && Math.abs(height(nodz.left) - height(nodz.right)) <= 1)
}
 
//log(height(root))
 
log("is balanced? " + isBalanced(root));