LeetCode-Easy刷題(29) Best Time to Buy and Sell Stock

Say you have an array for which the i^th element is the price of a given stock on day i.

If you were only permitted to complete at most one transaction (ie, buy one and sell one share of the stock), design an algorithm to find the maximum profit.

Example 1:

Input: [7, 1, 5, 3, 6, 4]
Output: 5

max. difference = 6-1 = 5 (not 7-1 = 6, as selling price needs to be larger than buying price)

Example 2:

Input: [7, 6, 4, 3, 1]
Output: 0

In this case, no transaction is done, i.e. max profit = 0.

一組數是按照時間順序的股票價格,如何操作一次能獲取到最大利潤.

   //動態規劃
    public int maxProfit(int[] prices) {
        //[7, 1, 5, 3, 6, 4]

        int local = 0;
        int global = 0;

        for (int i = 0; i < prices.length-1; i++) {
            local = Math.max(local+prices[i+1] - prices[i],0);//當前爲止最優解
            global = Math.max(local, global);
        }
        return global;
    }