array_problem.js

arrays = arrays.map(sort); // sort each sub-array
arrays = arrays.sort(function (ary) { return ary.length; }); // sort arrays by length, shortest will be first

var indexes = [];
for (i = 0; i < arrays.length; i++) {
	indexes[i] = 0;
}

var result = [];

while (indexes[0] < arrays[0].length) {
	var allEqual = true;
	for (i = 1; i < arrays.length; i++) {
		while (arrays[i][indexes[i]] < arrays[0][indexes[0]]) {
			indexes[i]++;
		}
		if (arrays[i][indexes[i]] != arrays[0][indexes[0]]) {
			allEqual = false;
			break;
		}
	}

	if (allEqual) {
		result.push(arrays[0][indexes[0]]);
	}

	indexes[0]++;
}