g0601_0700.s0638_shopping_offers.Solution Maven / Gradle / Ivy

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Java-based LeetCode algorithm problem solutions, regularly updated

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package g0601_0700.s0638_shopping_offers;

// #Medium #Array #Dynamic_Programming #Bit_Manipulation #Backtracking #Bitmask #Memoization
// #2022_03_21_Time_6_ms_(71.06%)_Space_42.6_MB_(71.63%)

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Solution {
    public int shoppingOffers(
            List price, List> special, List needs) {
        Map, Integer> map = new HashMap<>();
        shoppingOffersUtil(price, special, needs, map);
        return map.get(needs);
    }

    private int shoppingOffersUtil(
            List price,
            List> special,
            List needs,
            Map, Integer> map) {
        if (map.containsKey(needs)) {
            return map.get(needs);
        }
        Integer ans = computePrice(price, needs);
        for (int i = 0; i < special.size(); i++) {
            if (verify(special.get(i), needs)) {
                ans =
                        Math.min(
                                special.get(i).get(needs.size())
                                        + shoppingOffersUtil(
                                                price,
                                                special,
                                                updatedNeeds(needs, special.get(i)),
                                                map),
                                ans);
            }
        }
        map.put(needs, ans);
        return map.get(needs);
    }

    private List updatedNeeds(List needs, List special) {
        List updatedNeeds = new ArrayList<>(needs);
        for (int i = 0; i < needs.size(); i++) {
            updatedNeeds.set(i, updatedNeeds.get(i) - special.get(i));
        }
        return updatedNeeds;
    }

    private boolean verify(List special, List needs) {
        for (int i = 0; i < needs.size(); i++) {
            if (special.get(i) > needs.get(i)) {
                return false;
            }
        }
        return true;
    }

    private Integer computePrice(List price, List needs) {
        int ans = 0;
        for (int i = 0; i < needs.size(); i++) {
            ans += (needs.get(i) * price.get(i));
        }
        return ans;
    }
}