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Best Time to Buy and Sell Stock

Certification: Basic Level Accuracy: 0% Submissions: 0 Points: 8

Write a JavaScript program to find the maximum profit you can achieve from buying and selling a stock. You are given an array of prices where prices[i] is the price of a given stock on the ith day. You can choose a single day to buy one stock and choose 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: 
    • Consider all possible buy-sell combinations. 
    • Buy on day 2 (price = 1) and sell on day 5 (price = 6). 
    • Profit = 6 - 1 = 5. This is the maximum profit possible. 
    • Other combinations like buy at 1, sell at 5 gives profit of 4, which is less than 5.
    •
Example 2
    
  
  • Input: prices = [7, 6, 4, 3, 1]
    • 
  
  • Output: 0
    • 
  
  • Explanation: 
    • The prices are in descending order. 
    • There is no day where selling gives a profit.
    • Any buy day followed by a sell day results in a loss. 
    • Since we cannot achieve any profit, return 0.
    •
Constraints
    
  
  • 1 ≤ prices.length ≤ 10^5
    • 
  
  • 0 ≤ prices[i] ≤ 10^4
    • 
  
  • You must buy before you sell
    • 
  
  • Time Complexity: O(n)
    • 
  
  • Space Complexity: O(1)
    •
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Hint
Solution

Solution Hints

    
  
  • Keep track of the minimum price seen so far as you iterate through the array
    • 
  
  • For each price, calculate the profit if you sell on that day
    • 
  
  • The profit is the current price minus the minimum price seen so far
    • 
  
  • Keep track of the maximum profit encountered
    • 
  
  • Update the minimum price and maximum profit as you progress through the array
    •

Steps to solve by this approach:

 Step 1: Handle edge case where array has 1 or fewer elements (no profit possible).
 Step 2: Initialize minPrice with the first day's price and maxProfit as 0.
 Step 3: Iterate through the prices array starting from the second day.
 Step 4: For each day, calculate the potential profit by selling on that day (current price - minimum price so far).
 Step 5: Update the maximum profit if the current profit is greater.
 Step 6: Update the minimum price if the current price is lower than the previous minimum.
 Step 7: Return the maximum profit after checking all possible selling days.

Submitted Code :