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121. Best Time to Buy and Sell Stock

EasyOpen on LeetCodeProblem statement

Problem Statement

121. Best Time to Buy and Sell Stock

Easy


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:

C++ — alternative 1

Source file
class Solution {
public:
    int maxProfit(vector<int>& prices) {
        int maxm = INT_MIN, minm = INT_MAX;
        for (int p: prices){
            minm = min(minm, p);
            maxm = max(maxm, p-minm);
        }
        return maxm;
    }
};