http://blog.livedoor.jp/kinisoku/archives/4023190.html

poisonousWine.js

// Poison Wine
// http://blog.livedoor.jp/kinisoku/archives/4023190.html
(function() {
	var WINE_COUNT = 1000;

	// Phase0: Preparing
	var poisonousWineIdx = Math.floor(Math.random() * (WINE_COUNT + 1));
	var slaveNum = Math.floor((Math.log(WINE_COUNT) / Math.log(2)) + 1);
	var slaves = [];
	var i = 0, j = 0;
	for (; i < slaveNum; i++) {
		slaves.push(false);
	}

	// Phase1: Tasting
	// The poison is slow-acting,
	// so slaves must drink all wine to identify the poisonous one.
	for (i = 1; i <= WINE_COUNT; i++) {
		for (j = 0; j < slaveNum; j++) {
			if (!!((i >> (slaveNum - j - 1)) & 1)) {
				// current slave drinks this wine.
				slaves[j] |= (i === poisonousWineIdx);
			}
		}
	}

	// Phase2: Get Solution
	var answer = parseInt(slaves.join(''), 2);

	// Show Result
	console.log(poisonousWineIdx + ', ' + answer);

})();