解题思路：

动态规划

方法一：常规解法

class Solution {
    public int bestTiming(int[] prices) {
        int n = prices.length;
        if (n == 0) return 0;
        
        int[] dp = new int[n];
        int cost = prices[0];
        
        for (int i = 1; i < n; i++) {
            cost = Math.min(cost, prices[i]);
            dp[i] = Math.max(dp[i-1], prices[i] - cost);
        }
        
        return dp[n-1];
    }
}

方法二：优化解法

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