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

문제

주어진 배열은 일별 주식의 가격입니다. 배열의 인덱스는 날, 값은 가격입니다.

이 배열을 가지고 매매를 해서 최대의 수익을 반환하는 문제입니다.

설명

최대 수익을 저장하는 maxProfit와 최소 금액을 저장하는 min변수를 사용해서 최대 수익을 구하고, 그 값을 반환한다.

답

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var maxProfit = function(prices) {
  let min = Number.MAX_SAFE_INTEGER;
  let maxProfit = 0;
  for (let i = 0; i < prices.length; i++) {
    const price = prices[i];
    min = Math.min(min, price);
    maxProfit = Math.max(maxProfit, price - min);
  }
  return maxProfit;
};

LeetCode

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:

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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:

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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