【力扣】零钱兑换和零钱兑换2，动态规划算法

最大组合数和最小物品数

package day0325;/*** @description 动态规划* @date 2024/3/25*/
public class Demo2 {public static void main(String[] args) {// 3
//        int[] coins = {1, 2, 5};
//        int amount = 11;// 5
//        int[] coins = {1, 6, 7};
//        int amount = 30;// 20int[] coins = {186, 419, 83, 408};int amount = 6249;int count = getMinCoinCount(amount, coins);System.out.println(count);// 4
//        int[] coins = {1, 2, 5};
//        int amount = 5;// 0
//        int[] coins = {2};
//        int amount = 3;// 1
//        int[] coins = {10};
//        int amount = 10;//        int count = getMaxCombineCount(amount, coins);
//        System.out.println(count);}/*** <p>最大组合数</p>** @param amount 总金额（背包容量）* @param coins  零钱种类（物品种类）* @return*/private static int getMaxCombineCount(int amount, int[] coins) {int[] dp = new int[amount + 1];dp[0] = 1;for (int i = 0; i < coins.length; i++) {for (int j = coins[i]; j < dp.length; j++) {dp[j] = dp[j] + dp[j - coins[i]];}}return dp[amount];}/*** <p>最小物品数</p>** @param amount 总金额（背包容量）* @param coins  零钱种类（物品种类）* @return*/private static int getMinCoinCount(int amount, int[] coins) {int[] dp = new int[amount + 1];for (int i = 0; i < dp.length; i++) {dp[i] = amount + 1;}dp[0] = 0;for (int coin : coins) {for (int j = coin; j < dp.length; j++) {dp[j] = Math.min(dp[j], dp[j - coin] + 1);}}return dp[amount] > amount ? -1 : dp[amount];}}

打印最少数量组合

package day0325;import java.util.*;
import java.util.stream.IntStream;/*** @description 最少数量组合 记录是哪种组合* @date 2024/3/25*/
public class Demo1 {public static void main(String[] args) {// 3// 2*5   1*1// 11// int[] coins = {1, 2, 5};//int amount = 11;// [186, 186, 186, 419, 419, 419, 419, 419, 83, 83, 83, 83, 408, 408, 408, 408, 408, 408, 408, 408]int[] coins = {186, 419, 83, 408};int amount = 6249;// 20// 3*186   5*419   4*83   8*408// 558   2095   332   3264// 6249System.out.println(186 + 186 + 186 + 419 + 419 + 419 + 419 + 419 + 83 + 83 + 83 + 83 + 408 + 408 + 408 + 408 + 408 + 408 + 408 + 408);// 5// 5*6// 30// int[] coins = {1, 6, 7};// int amount = 30;// 记录组合Map<Integer, List<Integer>> amountListMap = IntStream.rangeClosed(0, amount).collect(HashMap::new, (map, i) -> map.put(i, new ArrayList<>()), HashMap::putAll);int[] dp = new int[amount + 1];Arrays.fill(dp, amount + 1);dp[0] = 0;for (int i = 0; i < coins.length; i++) {for (int j = 1; j < dp.length; j++) {if (j >= coins[i]) {int count = dp[j - coins[i]];int newCount = Math.min(dp[j], count + 1);if (newCount == count + 1) {List<Integer> currentList = new ArrayList<>();if (count == 0) {currentList.add(coins[i]);amountListMap.put(j, currentList);} else {List<Integer> otherList = amountListMap.get(j - coins[i]);currentList.addAll(otherList);currentList.add(coins[i]);amountListMap.put(j, currentList);}}dp[j] = newCount;}}}//        System.out.println(amountListMap);System.out.println(amountListMap.get(amount));System.out.println("-----------------------------------------------------------------------------------------------");//        System.out.println(Arrays.toString(dp));System.out.println(dp[amount] > amount ? -1 : dp[amount]);}}

打印所有的组合

package day0325;import java.util.*;
import java.util.stream.IntStream;/*** @description 所有的组合* @date 2024/3/25*/
public class Demo3 {public static void main(String[] args) {// 4// 1+1+1+1+1   1+1+1+2   1+2+2   5int[] coins = {1, 2, 5};int amount = 5;Map<Integer, List<List<Integer>>> everyAmountCombineListMap = IntStream.rangeClosed(0, 5).collect(HashMap::new, (map, i) -> map.put(i, new ArrayList<>()), HashMap::putAll);int[] dp = new int[amount + 1];dp[0] = 1;List<List<Integer>> zeroList = new ArrayList<>();List<Integer> innerZeroList = new ArrayList<>();innerZeroList.add(0);zeroList.add(innerZeroList);everyAmountCombineListMap.put(0, zeroList);for (int i = 0; i < coins.length; i++) {for (int j = coins[i]; j < dp.length; j++) {List<List<Integer>> amountCombineList = new ArrayList<>();if (j - coins[i] == 0) {List<Integer> innerList = new ArrayList<>();innerList.add(j);amountCombineList.add(innerList);} else {int otherIndex = j - coins[i];List<List<Integer>> otherList = everyAmountCombineListMap.get(otherIndex);for (List<Integer> l : otherList) {// 必须创建新的容器，不能破坏之前的数据List<Integer> currentList = new ArrayList<>(l);currentList.add(coins[i]);amountCombineList.add(currentList);}}if (dp[j] != 0) {List<List<Integer>> otherList = everyAmountCombineListMap.get(j);amountCombineList.addAll(otherList);}everyAmountCombineListMap.put(j, amountCombineList);dp[j] = dp[j] + dp[j - coins[i]];}}// [[5], [1, 2, 2], [1, 1, 1, 2], [1, 1, 1, 1, 1]]System.out.println(everyAmountCombineListMap);System.out.println(everyAmountCombineListMap.get(amount));System.out.println("--------------------------------------------------------------------------------------------------------------------");System.out.println(everyAmountCombineListMap.get(amount).size());System.out.println(dp[amount]);}}