LeetCode 1774. Closest Dessert Cost

DP

You would like to make dessert and are preparing to buy the ingredients. You have n ice cream base flavors and m types of toppings to choose from. You must follow these rules when making your dessert:

• There must be exactly one ice cream base.

• You can add one or more types of topping or have no toppings at all.

• There are at most two of each type of topping.

You are given three inputs:

• baseCosts, an integer array of length n, where each baseCosts[i] represents the price of the ith ice cream base flavor.

• toppingCosts, an integer array of length m, where each toppingCosts[i] is the price of one of the ith topping.

• target, an integer representing your target price for dessert.

You want to make a dessert with a total cost as close to target as possible.

Return the closest possible cost of the dessert to target. If there are multiple, return the lower one.

Example 1:

Input: baseCosts = [1,7], toppingCosts = [3,4], target = 10
Output: 10
Explanation: Consider the following combination (all 0-indexed):
- Choose base 1: cost 7
- Take 1 of topping 0: cost 1 x 3 = 3
- Take 0 of topping 1: cost 0 x 4 = 0
Total: 7 + 3 + 0 = 10.

Example 2:

Input: baseCosts = [2,3], toppingCosts = [4,5,100], target = 18
Output: 17
Explanation: Consider the following combination (all 0-indexed):
- Choose base 1: cost 3
- Take 1 of topping 0: cost 1 x 4 = 4
- Take 2 of topping 1: cost 2 x 5 = 10
- Take 0 of topping 2: cost 0 x 100 = 0
Total: 3 + 4 + 10 + 0 = 17. You cannot make a dessert with a total cost of 18.

Example 3:

Input: baseCosts = [3,10], toppingCosts = [2,5], target = 9
Output: 8
Explanation: It is possible to make desserts with cost 8 and 10. Return 8 as it is the lower cost.

Example 4:

Input: baseCosts = [10], toppingCosts = [1], target = 1
Output: 10
Explanation: Notice that you don't have to have any toppings, but you must have exactly one base.

Constraints:

• n == baseCosts.length

• m == toppingCosts.length

• 1 <= n, m <= 10

• 1 <= baseCosts[i], toppingCosts[i] <= 10^4

• 1 <= target <= 10^4

Solution:

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中文版解答Bilibili Link

class Solution {
public:
    int closestCost(vector<int>& baseCosts, vector<int>& toppingCosts, int target) {
        bool table[20010] = {false};
        int ans = -999999;
        for (int base : baseCosts) {
            table[base] = true;
        }
        
        for (int cost : toppingCosts) {
            for (int k = 1; k <= 2; k++) {
                for (int v = 20000; v >= 0; v--) {
                    if (v - cost >= 0 && table[v - cost] == true) {
                        table[v] = true;
                    }
                }
            }
        }
        
        for (int i = 1; i <= 20001; i++) {
            if (table[i] == true && abs(i - target) < abs(ans - target)) {
                ans = i;
            }
        }
        
        return ans;
    }
};