1 public class Bag {
  2 
  3     static class Item {// 定义一个物品
  4         String id; // 物品id
  5         int size = 0;// 物品所占空间
  6         int value = http://www.mamicode.com/0;// 物品价值
  7 
  8         static Item newItem(String id, int size, int value) {
  9             Item item = new Item();
 10             item.id = id;
 11             item.size = size;
 12             item.value =http://www.mamicode.com/ value;
 13             return item;
 14         }
 15 
 16         public String toString() {
 17             return this.id;
 18         }
 19     }
 20 
 21     static class OkBag { // 定义一个打包方式
 22         List<Item> Items = new ArrayList<Item>();// 包里的物品集合
 23 
 24         OkBag() {
 25         }
 26 
 27         int getValue() {// 包中物品的总价值
 28             int value = http://www.mamicode.com/0;
 29             for (Item item : Items) {
 30                 value += item.value;
 31             }
 32             return value;
 33         };
 34 
 35         int getSize() {// 包中物品的总大小
 36             int size = 0;
 37             for (Item item : Items) {
 38                 size += item.size;
 39             }
 40             return size;
 41         };
 42 
 43         public String toString() {
 44             return String.valueOf(this.getValue()) + " ";
 45         }
 46     }
 47 
 48     // 可放入包中的备选物品
 49     static Item[] sourceItems = { Item.newItem("4号球", 4, 5), Item.newItem("5号球", 5, 6), Item.newItem("6号球", 6, 7) };
 50     static int bagSize = 10; // 包的空间
 51     static int itemCount = sourceItems.length; // 物品的数量
 52 
 53     // 保存各种情况下的最优打包方式 第一维度为物品数量从0到itemCount,第二维度为包裹大小从0到bagSize
 54     static OkBag[][] okBags = new OkBag[itemCount + 1][bagSize + 1];
 55 
 56     static void init() {
 57         for (int i = 0; i < bagSize + 1; i++) {
 58             okBags[0][i] = new OkBag();
 59         }
 60 
 61         for (int i = 0; i < itemCount + 1; i++) {
 62             okBags[i][0] = new OkBag();
 63         }
 64     }
 65 
 66     static void doBag() {
 67         init();
 68         for (int iItem = 1; iItem <= itemCount; iItem++) {
 69             for (int curBagSize = 1; curBagSize <= bagSize; curBagSize++) {
 70                 okBags[iItem][curBagSize] = new OkBag();
 71                 if (sourceItems[iItem - 1].size > curBagSize) {// 当前物品大于包空间.肯定不能放入包中.
 72                     okBags[iItem][curBagSize].Items.addAll(okBags[iItem - 1][curBagSize].Items);
 73                 } else {
 74                     int notIncludeValue = http://www.mamicode.com/okBags[iItem - 1][curBagSize].getValue();// 不放当前物品包的价值
 75                     int freeSize = curBagSize - sourceItems[iItem - 1].size;// 放当前物品包剩余空间
 76                     int includeValue = http://www.mamicode.com/sourceItems[iItem - 1].value + okBags[iItem - 1][freeSize].getValue();// 当前物品价值+放了当前物品后剩余包空间能放物品的价值
 77                     if (notIncludeValue < includeValue) {// 放了价值更大就放入.
 78                         okBags[iItem][curBagSize].Items.addAll(okBags[iItem - 1][freeSize].Items);
 79                         okBags[iItem][curBagSize].Items.add(sourceItems[iItem - 1]);
 80                     } else {// 否则不放入当前物品
 81                         okBags[iItem][curBagSize].Items.addAll(okBags[iItem - 1][curBagSize].Items);
 82                     }
 83                 }
 84 
 85             }
 86         }
 87     }
 88 
 89     public static void main(String[] args) {
 90         Bag.doBag();
 91         for (int i = 0; i < Bag.itemCount + 1; i++) {// 打印所有方案中包含的物品
 92             for (int j = 0; j < Bag.bagSize + 1; j++) {
 93                 System.out.print(Bag.okBags[i][j].Items);
 94             }
 95             System.out.println("");
 96         }
 97 
 98         for (int i = 0; i < Bag.itemCount + 1; i++) {// 打印所有方案中包的总价值
 99             for (int j = 0; j < Bag.bagSize + 1; j++) {
100                 System.out.print(Bag.okBags[i][j]);
101             }
102             System.out.println("");
103         }
104 
105         OkBag okBagResult = Bag.okBags[Bag.itemCount][Bag.bagSize];
106         System.out.println("最终结果为:" + okBagResult.Items.toString() + okBagResult);
107 
108     }
109 
110 }