Apply discount to prices

Link: https://leetcode.com/problems/apply-discount-to-prices/

Solution:

Topics: subarray

Intuition
The code kind of speaks for itself in this case. Just split the string by spaces and check if the first character is $, if so then check if everything following $ is a digit, if so apply the discount.

The discount calculation must be converted into the appropriate multiplication. For example, a discount of 80% is a multiplication by 0.2. Therefore the formula is as follows:

multiplier = (100 - discount)/100

Implementation

def apply_discount(sentence, discount):
	words = sentence.split(' ')
	for i in range(len(words)):
		if words[i][0] != '$':
			continue
		price = words[i][1:]
		if price.isdigit():
			words[i] = f"${(int(price) * ((100 - discount)/100)):.2f}"
	return ' '.join(words)
 
#time: o(n)
#memory: o(1)

Visual

Review 1
Most of these parsing problems require splitting. Split by spaces, if the start is $ and the rest is a digit, apply the discount. Join back into a sentence at the end.

review