leetcode 121) Best Time to Buy and Sell Stock

LV. Easy 😎

https://leetcode.com/problems/best-time-to-buy-and-sell-stock/

Best Time to Buy and Sell Stock - LeetCode

 

문제

You are given an array prices where prices[i] is the price of a given stock on the ith day.

You want to maximize your profit by choosing a single day to buy one stock and choosing a different day in the future to sell that stock.

Return the maximum profit you can achieve from this transaction. If you cannot achieve any profit, return 0.

 

Example 1:

Input: prices = [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.
Note that buying on day 2 and selling on day 1 is not allowed because you must buy before you sell.

Example 2:

Input: prices = [7,6,4,3,1]
Output: 0
Explanation: In this case, no transactions are done and the max profit = 0.

 

Constraints:

• 1 <= prices.length <= 10^5
• 0 <= prices[i] <= 10^4

 

문제 해결법

min : 최솟값

ans : maximum profit

 

처음 값을 min값으로 두고 시작한다.

 

min > prices[i] : ans 값을 계산해준다.

min < prices[i] : min 값을 prices[i]로 바꿔준다.

 

오늘 문제는 간단하게 해결 완료! 🥳

 

해결 코드

class Solution {
public:
	int maxProfit(vector<int>& prices) {
		int min = prices[0];
		int ans = 0;

		for (int i = 1; i < prices.size(); ++i) {
			if (prices[i] > min)
				ans = max(ans, prices[i] - min);
			else if (prices[i] < min)
				min = prices[i];
		}
		return ans;
	}
};