###### Technical Articles # Easy way to perform Stock Buy And Sell algorithm in SAP BTP ABAP(Steampunk), JS & Python

## Introduction

This is part of the Easy way to write algorithms in ABAP: Series 01. For more algorithms, please check the main blog-post.

## Problem

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:

```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:

```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`

## Solution

Time Complexity: O(n)

Space Complexity: O(1)

### ABAP

``````CLASS zstockbuysell DEFINITION
PUBLIC
FINAL
CREATE PUBLIC .

PUBLIC SECTION.

* Mandatory declaration

PROTECTED SECTION.
PRIVATE SECTION.

TYPES ty_prices TYPE STANDARD TABLE OF i WITH DEFAULT KEY.

IMPORTING lt_prices            TYPE ty_prices
RETURNING VALUE(rv_max_profit) TYPE i.

ENDCLASS.

out->write( |{ StockBuySell( VALUE #( ( 7 ) ( 1 ) ( 5 ) ( 3 ) ( 6 ) ( 4 ) ) ) }| ).
ENDMETHOD.

DATA(lv_min_price) = lt_prices[ 1 ].

LOOP AT lt_prices ASSIGNING FIELD-SYMBOL(<lfs_wa>).
lv_min_price = nmin( val1 = lv_min_price
val2 = <lfs_wa> ).
rv_max_profit = nmax( val1 = rv_max_profit
val2 = ( <lfs_wa> - lv_min_price ) ).
ENDLOOP.

UNASSIGN <lfs_wa>.
FREE lv_min_price.

ENDMETHOD.

ENDCLASS.``````

### JavaScript

``````var maxProfit = function(prices) {

var lv_min_price = prices,
lv_max_profit = 0;

for(let i = 0; i < prices.length; i++){
lv_min_price = Math.min(lv_min_price, prices[i]);
lv_max_profit = Math.max(lv_max_profit, (prices[i] - lv_min_price));
}

return lv_max_profit;

};``````

### Python

``````class Solution:
def maxProfit(self, prices: List[int]) -> int:

lv_min_price = prices
lv_max_profit = 0

for i in range(0, len(prices)):
lv_min_price = min(lv_min_price, prices[i])
lv_max_profit = max(lv_max_profit, (prices[i] - lv_min_price))

return lv_max_profit``````

N.B: For ABAP, I am using SAP BTP ABAP Environment 2211 Release.

Happy Coding! 🙂

### Assigned Tags

1 Comment
You must be Logged on to comment or reply to a post. Here is a Scheme version:

``````(define (max-profit lst)
(define (iter lst min-price max-profit)
(if (null? lst)
max-profit
(let ((price (car lst)))
(iter (cdr lst)
(min price min-price)
(max max-profit (- price min-price))))))
(iter lst (car lst) 0))``````

Disclaimer: It is a tweaked ChatGPT output. I checked with abap Scheme:

``````(max-profit '(7 1 5 3 6 4))
=> 5
(max-profit '(7 6 4 3 1))
=> 0
(max-profit '(100 180 260 310 40 535 695))
=> 655``````

best regards,

Jacques Nomssi Nzali