算法 Java Leetcode Golang

Design an algorithm to find the maximum profit.

Question

Say you have an array for which the ith element is the price of a given stock on day i. If you were only permitted to complete at most one transaction (ie, buy one and sell one share of the stock), design an algorithm to find the maximum profit.
See it on Leetcode

Example 1

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Input: [7, 1, 5, 3, 6, 4]
Output: 5
max. difference = 6-1 = 5 
Not 7-1 = 6, as selling price needs to be larger than buying price.

Example 2

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Input: [7, 6, 4, 3, 1]
Output: 0
In this case, no transaction is done, i.e. max profit = 0.

Hint

Brute force approach may result in Time Limit Exceeded. Try greedy approach.

Solution in Java and Golang

  • java
  • go
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public class Solution {
    public int maxProfit(int[] prices) {
        int minPrice = Integer.MAX_VALUE;
        int maxProfit = 0;
        for (int i : prices) {
            if (i < minPrice) {
                minPrice = i;
            } else if (i - minPrice > maxProfit) {
                maxProfit = i - minPrice;
            }
        }
        return maxProfit;
    }
}