public int maxProfit(int[] prices) {
		if(prices == null || prices.length == 0) return 0;
		int max = 0, min = prices[0];
		for(int i = 1; i < prices.length; i++) {
			if(prices[i] > min && prices[i] - min > max) max = prices[i] - min;
			else if(prices[i] < min) min = prices[i];
		}
		return max;
	}