Question

2288. Apply Discount to Prices

中文文档

Description

A sentence is a string of single-space separated words where each word can contain digits, lowercase letters, and the dollar sign '

A sentence is a string of single-space separated words where each word can contain digits, lowercase letters, and the dollar sign '$'. A word represents a price if it is a sequence of digits preceded by a dollar sign.

#39;. 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 sentence representing a sentence and an integer discount. For each word representing a price, apply a discount of discount% 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 10 digits.

 

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
• sentence consists of lowercase English letters, digits, ' ', and '$'.
• sentence does not have leading or trailing spaces.
• All words in sentence are separated by a single space.
• All prices will be positive numbers without leading zeros.
• All prices will have at most 10 digits.
• 0 <= discount <= 100

Solutions

Solution 1

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)

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 {
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(' ');
}