剑指offer-3.11-63

class Solution {
    public int maxProfit(int[] prices) {
        int maxProfit = 0;
        for (int i = 0; i < prices.length - 1; i++) {
            for (int j = i + 1; j < prices.length; j++) {
                if (prices[j] - prices[i] > maxProfit) {
                    maxProfit = prices[j] - prices[i];
                }
            }
        }
        return maxProfit;
    }
}

class Solution {
    public int maxProfit(int[] prices) {
        int profit = 0, cost = Integer.MAX_VALUE;
        for (int price : prices) {
            cost = Math.min(cost, price);
            profit = Math.max(profit, price - cost);
        }
        return profit;
    }
}