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Formatted question description: https://leetcode.ca/all/2288.html
2288. Apply Discount to Prices
- Difficulty: Medium.
- Related Topics: String.
- Similar Questions: Multiply Strings, Apply Discount Every n Orders.
Problem
A sentence is a string of single-space separated words where each word can contain digits, lowercase letters, and the dollar sign ```’
Solution (Java, C++, Python)
-
Explain:
nope.
Complexity:
- Time complexity : O(n).
-
Space complexity : O(n). ```. A word represents a price if it is a sequence of digits preceded by a dollar sign.
- For example,
"$100","$23", and"$6"represent prices while"100","$", and"$1e5"do not.
You are given a string
sentencerepresenting a sentence and an integerdiscount. For each word representing a price, apply a discount ofdiscount%on the price and update the word in the sentence. All updated prices should be represented with exactly two decimal places.Return a string representing the modified sentence.
Note that all prices will contain at most
10digits.Example 1:
Input: sentence = "there are $1 $2 and 5$ candies in the shop", discount = 50 Output: "there are $0.50 $1.00 and 5$ candies in the shop" Explanation: The words which represent prices are "$1" and "$2". - A 50% discount on "$1" yields "$0.50", so "$1" is replaced by "$0.50". - A 50% discount on "$2" yields "$1". Since we need to have exactly 2 decimal places after a price, we replace "$2" with "$1.00".Example 2:
Input: sentence = "1 2 $3 4 $5 $6 7 8$ $9 $10$", discount = 100 Output: "1 2 $0.00 4 $0.00 $0.00 7 8$ $0.00 $10$" Explanation: Applying a 100% discount on any price will result in 0. The words representing prices are "$3", "$5", "$6", and "$9". Each of them is replaced by "$0.00".Constraints:
-
1 <= sentence.length <= 105 -
sentenceconsists of lowercase English letters, digits,' ', and ```’
Solution (Java, C++, Python)
class Solution { public String discountPrices(String sentence, int discount) { String[] words = sentence.split(" "); StringBuilder sb = new StringBuilder(); for (String word : words) { sb.append(applyDiscount(word, discount)); sb.append(" "); } sb.deleteCharAt(sb.length() - 1); return sb.toString(); } private String applyDiscount(String s, int discount) { if (s.charAt(0) == '$' && s.length() > 1) { long price = 0; for (int i = 1; i < s.length(); i++) { if (!Character.isDigit(s.charAt(i))) { // Error case. We could also use Long.parseLong() here. return s; } price *= 10; price += (s.charAt(i) - '0') * (100 - discount); } String stringPrice = String.valueOf(price); if (price < 10) { return "$0.0" + stringPrice; } if (price < 100) { return "$0." + stringPrice; } return "$" + stringPrice.substring(0, stringPrice.length() - 2) + "." + stringPrice.substring(stringPrice.length() - 2); } return s; } }Explain:
nope.
Complexity:
- Time complexity : O(n).
-
Space complexity : O(n). ```.
-
sentencedoes not have leading or trailing spaces. -
All words in
sentenceare separated by a single space. -
All prices will be positive numbers without leading zeros.
-
All prices will have at most
10digits. 0 <= discount <= 100
Solution (Java, C++, Python)
############ class Solution { public String discountPrices(String sentence, int discount) { String[] words = sentence.split(" "); for (int i = 0; i < words.length; ++i) { if (check(words[i])) { double t = Long.parseLong(words[i].substring(1)) * (1 - discount / 100.0); words[i] = String.format("$%.2f", t); } } return String.join(" ", words); } private boolean check(String s) { if (s.charAt(0) != '$' || s.length() == 1) { return false; } for (int i = 1; i < s.length(); ++i) { if (!Character.isDigit(s.charAt(i))) { return false; } } return true; } } -
class Solution: def discountPrices(self, sentence: str, discount: int) -> str: ans = [] for w in sentence.split(): if w[0] == '$' and w[1:].isdigit(): w = f'${int(w[1:]) * (1 - discount / 100):.2f}' ans.append(w) return ' '.join(ans) ############ # 2288. Apply Discount to Prices # https://leetcode.com/problems/apply-discount-to-prices/ class Solution: def discountPrices(self, sentence: str, discount: int) -> str: def getDiscount(x): # print(x) if discount == 100: return "0.00" res = float(x) * float(1 - discount / 100) return "{:.2f}".format(res) res = [] for x in sentence.split(" "): if x[0] != "$": res.append(x) else: count = 0 for c in x: if c == "$": count += 1 elif c in string.ascii_lowercase: count += 1 if len(x) > 1 and x[0] == "$" and count == 1: res.append(x[0] + str(getDiscount(x[1:]))) else: res.append(x) return " ".join(res) -
class Solution { public: string discountPrices(string sentence, int discount) { istringstream is(sentence); string w; string ans; auto check = [](string s) { if (s[0] != '$' || s.size() == 1) { return false; } for (int i = 1; i < s.size(); ++i) { if (!isdigit(s[i])) { return false; } } return true; }; while (is >> w) { if (check(w)) { long long v = stoll(w.substr(1)) * (100 - discount); char t[20]; sprintf(t, "$%lld.%02lld", v / 100, v % 100); ans += t; } else { ans += w; } ans += ' '; } ans.pop_back(); return ans; } }; -
func discountPrices(sentence string, discount int) string { words := strings.Split(sentence, " ") for i, w := range words { if w[0] == '$' { if v, err := strconv.Atoi(w[1:]); err == nil { words[i] = fmt.Sprintf("$%.2f", float64(v*(100-discount))/100) } } } return strings.Join(words, " ") } -
function discountPrices(sentence: string, discount: number): string { const sell = (100 - discount) / 100; let reg = new RegExp(/^(\$)(([1-9]\d*\.?\d*)|(0\.\d*))$/g); let arr = sentence.split(' ').map(d => { if (!reg.test(d)) return d; return d.replace(reg, (s, $1, $2) => { return `$${(sell * $2).toFixed(2)}`; }); }); return arr.join(' '); }
Explain:
nope.
Complexity:
- Time complexity : O(n).
- Space complexity : O(n).