121. 买卖股票的最佳时机

题目链接：https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock/submissions/

执行用时：1 ms, 在所有 Java 提交中击败了100.00%的用户
内存消耗：51.2 MB, 在所有 Java 提交中击败了79.45%的用户

class Solution {
    public int maxProfit(int[] prices) {
        int minPrice = 100001, profit = 0;
        int length = prices.length;
        for(int i = 0; i < length; i++) {
           if (minPrice > prices[i]) {
               minPrice = prices[i];
           } else if (prices[i] - minPrice > profit) {
               profit = prices[i] - minPrice;
           }
        }
        return profit;
    }
}

Swift

class Solution {
    func maxProfit(_ prices: [Int]) -> Int {
        var profit = 0 //记录最大利润
        var minValue: Int = prices[0] //记录数组中访问过的最小值
        let n = prices.count
        for i in 0 ..< n {
            minValue = min(minValue, prices[i])
            profit = max(prices[i] - minValue, profit)
        }
        return profit
    }
}