gistfile1.js

//given an array of integers (x), and an integer (y), returns true if any two of the integers in x add up to y.
var addsToY = function(arr, y) {
	for(var i = 0; i < arr.length; i ++) {
		for (var j = i + 1; j < arr.length; j++) {
			if(arr[i] + arr[j] === y) return true;
		}
	}
	return false;
}

//Helper function to find combination arrays.
var combinations = function(arr, n) {
	var result = [];
	if(n == 1) {
		for(var i = 0; i < arr.length; i++) {
			result.push([arr[i]]);
		}
		return result;
	} else {
		for(var i = 0; i < arr.length; i++){
			var currentArr = arr.slice(i+1);
			var temp = combinations(currentArr, n-1);
			for(var j = 0; j < temp.length; j++){
				temp[j].push(arr[i]);
			}
			result = result.concat(temp);
		}

	}
	return result;
}

//given the above arguments and an additional integer (z), returns true if any z of the integers in x add up to y.
var zAddsToY = function(arr, y, z) {
	if(z < 0) return false;
	else if(z === 1) { return arr.indexOf(y) > -1 ? true : false;}
	else {
		var result = [];
		var arrCombinations = combinations(arr, z);
		for(var i = 0; i < arrCombinations.length; i++) {
			var total = 0;
			for(var j = 0; j < arrCombinations[i].length; j++) {
				total += arrCombinations[i][j];
			}
			if(total === y) return true;
		}
	}
	return false;
}