[LeetCode] DP - 121. Best Time to Buy and Sell Stock

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 <= 105
• 0 <= prices[i] <= 104

코드

const maxProfit = (prices) => {
    let left = 0;
    let right = 1;
    let max = 0;

    while(right < prices.length) {
        if(prices[right] > prices[left]) {
            max = Math.max(prices[right] - prices[left], max);

        } else {
            left = right;
        }
        right++;
    }

    return max;
}