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Minimum Total Price After Applying Discounts

Medium
leetcode· Java· 2026-08-09Problem link ↗

Runtime

46 ms

Beats 34.48%

Memory

146.1 MB

Beats 9.76%

Problem

You are given two integer arrays prices and discounts.

The value prices[i] represents the price of the ith item, and discounts[j] represents a discount percentage.

You may apply discounts subject to the following rules:

  • Each discount can be applied to at most one item.
  • Each item can receive at most one discount.
  • An item may also receive no discount.

If a discount of d percent is applied to an item with price p, its final price becomes (p * (100 - d)) / 100. The final price is not rounded.

Return the minimum possible sum of final prices after assigning discounts optimally. Answers within 10-5 of the actual answer will be accepted.

 

Example 1:

Input: prices = [10,30,21], discounts = [50,60]

Output: 32.50000

Explanation:

  • Apply discounts[1] = 60 to prices[1] = 30, thus 30 * (100 - 60) / 100 = 12.
  • Apply discounts[0] = 50 to prices[2] = 21, thus 21 * (100 - 50) / 100 = 10.5.
  • prices[0] = 10 receives no discount, so it stays 10.

The total is 12 + 10.5 + 10 = 32.50000, which is the minimum possible.

Example 2:

Input: prices = [100,70], discounts = [10,40,50]

Output: 92.00000

Explanation:​​​​​​​

  • Apply discounts[2] = 50 to prices[0] = 100, thus 100 * (100 - 50) / 100 = 50.
  • Apply discounts[1] = 40 to prices[1] = 70, thus 70 * (100 - 40) / 100 = 42.

The total is 50 + 42 = 92.00000, which is the minimum possible.

Example 3:

Input: prices = [7,3,9], discounts = [100,100]

Output: 3.00000

Explanation:

  • Apply discounts[0] = 100 to prices[2] = 9, thus 9 * (100 - 100) / 100 = 0.
  • Apply discounts[1] = 100 to prices[0] = 7, thus 7 * (100 - 100) / 100 = 0.
  • prices[1] = 3 receives no discount, so it stays 3.

The total is 0 + 0 + 3 = 3.00000, which is the minimum possible.

 

Constraints:

  • 1 <= prices.length, discounts.length <= 105
  • 1 <= prices[i] <= 105
  • 1 <= discounts[j] <= 100

Solution

Java
import java.util.Arrays;
class Solution {    
    public double minPrice(int[] prices, int[] discounts) {        Arrays.sort(prices);      // ascending  
Arrays.sort(discounts);   // ascending        
int n = prices.length;        
                                                           
int k = discounts.length;       
double total = 0;
int di = k - 1; 
for (int i = n - 1; i >= 0; i--) {
    if (di >= 0) { 
        total += prices[i] * (100.0 - discounts[di]) / 100.0;                
    di--;            } else {                
    
        total += prices[i];              
    }        
}        
                                                           return total;    
                                                          }
}