wren/benchmark/binary_trees.js

/* The Great Computer Language Shootout
http://shootout.alioth.debian.org/
contributed by Isaac Gouy */

function TreeNode(left, right, item) {
  this.left = left;
  this.right = right;
  this.item = item;
}

TreeNode.prototype.itemCheck = function() {
  if (this.left == null) return this.item;
  return this.item + this.left.itemCheck() - this.right.itemCheck();
}

function bottomUpTree(item, depth) {
  if (depth > 0) {
    return new TreeNode(
        bottomUpTree(2 * item - 1, depth - 1),
        bottomUpTree(2 * item, depth - 1), item);
  }

  return new TreeNode(null, null, item);
}

var minDepth = 4;
var maxDepth = 14;
var stretchDepth = maxDepth + 1;

var start = process.hrtime();

var check = bottomUpTree(0, stretchDepth).itemCheck();
console.log("stretch tree of depth " + stretchDepth + "\t check: " + check);

var longLivedTree = bottomUpTree(0, maxDepth);
for (var depth = minDepth; depth <= maxDepth; depth += 2) {
  var iterations = 1 << (maxDepth - depth + minDepth);

  check = 0;
  for (var i = 1; i <= iterations; i++) {
    check += bottomUpTree(i, depth).itemCheck();
    check += bottomUpTree(-i, depth).itemCheck();
  }

  console.log(iterations * 2 + "\t trees of depth " + depth +
      "\t check: " + check);
}

console.log("long lived tree of depth " + maxDepth + "\t check: "
    + longLivedTree.itemCheck());

var elapsed = process.hrtime(start);
elapsed = elapsed[0] + elapsed[1] / 1000000000;
console.log("elapsed: " + elapsed);