Wolf of Wall Street 2 - Amazon Top Interview Questions

Problem Statement :

Given a list of integers prices representing the stock prices of a company in chronological order, return the maximum profit you could have made from buying and selling that stock once.

You must buy before you can sell it.

Note: You are not required to buy or sell the stock.


n ≤ 100,000 where n is the length of prices

Example 1

prices = [9, 11, 8, 5, 7, 10]


You can buy at 5 and sell at 10.

Example 2

prices = [1, 2, 3, 4, 5, 6, 7, 8, 9]


You can buy at 1 and sell at 9.

Example 3

prices = [9, 8, 7, 6, 5, 4, 3, 2, 1]


The stock's only going down so we don't buy at all.

Solution :


                        Solution in C++ :

int solve(vector<int>& prices) {
    int profit = 0;
    int low = INT_MAX;

    for (auto x : prices) {
        low = min(low, x);

        profit = max(profit, x - low);
    return profit;

                        Solution in Java :

import java.util.*;

class Solution {
    public int solve(int[] prices) {
        int len = prices.length;
        if (len == 0 || len == 1)
            return 0;
        int min = prices[0], diff = 0;
        for (int i = 1; i < len; i++) {
            if (prices[i] - min > diff) {
                diff = prices[i] - min;
            if (prices[i] < min) {
                min = prices[i];
        return diff;

                        Solution in Python : 
class Solution:
    def solve(self, prices):
        if len(prices) < 2:
            return 0
        maxProfit = 0
        min = prices[0]
        for i in prices[1:]:
            if i - min > maxProfit:
                maxProfit = i - min
            if i < min:
                min = i
        return maxProfit

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