package thinking;import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;import org.junit.Test;/* QUESTION : optimal loading problem* DESCRIBTION : Now we have some boxs need to be loaded into a ship which the limit of its load capacity is C ,and*                 every weight of box is designated by the user. The Volume(体积) of this ship isn't limit. So how can *                 we load boxes as many as possible? * * */
class Ship{private int capacity;public void setCapacity(int capacity) {this.capacity = capacity;}public int getCapacity() {return capacity;}
}class Box{private int weight;public void setWeight(int weight) {this.weight = weight;}public int getWeight() {return weight;}
}public class Greedy {Ship ship = new Ship();Box box1 = new Box();Box box2 = new Box();Box box3 = new Box();Box box4 = new Box();Box box5 = new Box();@Testpublic void lookingForTheBestChoise(){// step 1 : initialize the info of ship and boxesSystem.out.println("please input the capacity of ur ship!");Scanner scanner = new Scanner(System.in);int capacity = scanner.nextInt();ship.setCapacity(capacity);System.out.println("please input the werght of ur boxes(5)!");int b1 = scanner.nextInt();int b2 = scanner.nextInt();int b3 = scanner.nextInt();int b4 = scanner.nextInt();int b5 = scanner.nextInt();box1.setWeight(b1);box2.setWeight(b2);box3.setWeight(b3);box4.setWeight(b4);box5.setWeight(b5);List<Box> boxes = new ArrayList<Box>();boxes.add(box1);boxes.add(box2);boxes.add(box3);boxes.add(box4);boxes.add(box5);List<Box> sortedList = sort(boxes);// step 2 : looking for the best solution step by stepint index = 0;while(capacity != 0){if(sortedList.get(0).getWeight() > capacity){System.out.println("ur capacity of ship is too light!");System.exit(0);}else{if(sortedList.get(index).getWeight() < capacity){System.out.print(sortedList.get(index).getWeight());capacity = capacity-sortedList.get(index).getWeight();index++;}else{System.out.println("no more can be loaded");System.exit(0);}}}}List<Box> sort(List<Box> boxes){//List<Box> sortedList = new ArrayList<Box>();for(int i = 0; i<boxes.size(); ++i){for(int j = 0; j < boxes.size()-i-1; ++j){int tempWeight;if(boxes.get(j).getWeight() > boxes.get(j+1).getWeight()){tempWeight = boxes.get(j).getWeight();boxes.get(j).setWeight(boxes.get(j+1).getWeight()); boxes.get(j+1).setWeight(tempWeight);}}}for (Box box : boxes) {System.out.println(box.getWeight());}return boxes;}public static void main(String[] args) {//Scanner s = new Scanner(System.in);
        }
}

package thinking;import java.util.Scanner;import org.junit.Test;/* QUESTION : A traveler has a backpack of up to Mkg, and now has n items, each weighing W1, W2,...Wn.The value of*               each piece are respectively C1, C2,...,Cn.the number of each item if enough. The maxinum value of a *               traveler.* */public class PackageQuestion {int capacity;int n; // 物件的数量
    @Testpublic void getMaxValue(){// 输入物件信息System.out.println("please input the capacity of backpack!");Scanner sca = new Scanner(System.in);capacity = sca.nextInt();System.out.println("please input the number of the items!");n = sca.nextInt();int[] weight = new int[n]; // 重量数组int[] value = new int[n];  // 对应的价值数组int[] index = new int[n];  // 一个额外的记录变化的数组，后面会进行排序交换，所以每一个物品都要贴一个标签System.out.println("please input the weight of these items!");for(int i = 0; i<n; ++i){weight[i] = sca.nextInt();}System.out.println("please input the value of these items!");for(int i =0; i<n; ++i){value[i] = sca.nextInt();}//下面就是重场戏了// 因为每个物品的重量和价值都不一样，直观可比性不强，所以我们想要一个可以直观比较的参数，进而想到单位重量下的价值double[] ev = new double[n]; // 单位重量下的价值数组for(int i = 0; i<n; ++i){double v = (double)value[i] / (double)weight[i];ev[i] = v;index[i] = i; //初始化标志
        }// 然后下面就是一个复杂的按照价值的由高到低的排序的过程,采用选择排序或者冒泡都可以。for(int i = 0; i<n-1; ++i){for(int j = i+1; j<n; ++j){if(ev[i] < ev[j]){// 前面的单位重量下的价值小于后面的，就交换位置double temp;temp = ev[i];ev[i] = ev[j];ev[j] = temp;// 位置的改变后，一定要注意标志位置的也要改变int temp3 = index[i];index[i] = index[j];index[j] = temp3;}}}// 用两个新数组来装这个排好序的重量和价值int[] wei = new int[n];int[] val = new int[n];for(int i = 0; i<n; ++i){wei[i] = weight[index[i]];val[i] = value[index[i]];}//排好序后的监测一下System.out.println("weight:");for(int i = 0; i<n; ++i){System.out.print(wei[i]+"\t");}System.out.println("value:");for(int i = 0; i<n; ++i){System.out.print(val[i]+"\t");}System.out.println("index:");for(int i = 0; i<n; ++i){System.out.print(index[i]+"\t");}//排好序后就开始进行贪心子结构最优化int x = 0;while(capacity > 0){if(wei[0] > capacity){System.out.println("ur backpack is too small, get changed!");System.exit(0);}else{if(wei[x] < capacity){System.out.println("get the value is "+val[x]+" item");capacity = capacity-wei[x];x++;}else{System.out.println("ur backpack can't pack any more!");System.exit(0);}}}}public static void main(String[] args) {}
}