122.md

122. Best Time to Buy and Sell Stock II

Description

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

Design an algorithm to find the maximum profit. You may complete as many transactions as you like (ie, buy one and sell one share of the stock multiple times). However, you may not engage in multiple transactions at the same time (ie, you must sell the stock before you buy again).

Thinking Process

1. Greedy approach, as soon as the price is higher than yesterday, sell it

Code

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

Complexity

1. Time complexity is O(n)
2. Space complexity is O(1)