[LeetCode] Best Time to Buy and Sell Stock

문제

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

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

Note that you cannot sell a stock before you buy one.

Example 1:

Input: [7,1,5,3,6,4] Output: 5 Explanation: Buy on day 2 (price = 1) and sell on day 5 (price = 6), profit = 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 Explanation: In this case, no transaction is done, i.e. max profit = 0.

 

Approach

Brute force로 해도 되고

최대 이익을 내려면 최대한 싸게 사서 최대한 비싸게 파는 것이 핵심이니

초기 구매가격을 배열의 첫 원소로 한다음

배열을 훑으며 기존 가격보다 싼 가격이 나오면 구매 가격으로 바꾸고

비싼 가격이 나오면 이익을 측정한다.

 

Code

https://github.com/chi3236/algorithm/blob/master/LeetCode_BestTimeToBuyAndSellStock.cpp

chi3236/algorithm