package com.dam.heuristic.algorithm.vns.dam.v2;
import java.util.*;
public class VnsApiV2 {
    //迭代次数
    private int GEN_NUM;
    //变领域下降搜索时，每种领域搜索方式的搜索次数
    private int SEARCH_NUM;
    //城市数量
    private int CITY_NUM;
    //多少次没有找到更优解退出迭代
    private int NUM_OF_NOT_FIND_BETTER_SOLUTION;
    //距离矩阵
    private double[][] distanceMatrix;
    public VnsApiV2(int genNum, int searchNum, int numOfNotFindBetterSolution, double[][] distanceMatrix) {
        this.GEN_NUM = genNum;
        this.SEARCH_NUM = searchNum;
        this.NUM_OF_NOT_FIND_BETTER_SOLUTION = numOfNotFindBetterSolution;
        this.distanceMatrix = distanceMatrix;
        this.CITY_NUM = distanceMatrix[0].length;
    }
    /**
     * 求解
     */
    public int[] solve() {
        声明变量
        //开始求解时间
        long startTime = System.currentTimeMillis();
        ///最优解
        //序列
        int[] localSequence = new int[this.distanceMatrix[0].length];
        //最优序列
        int[] bestSequence;
        //最优序列对应的目标函数值
        double bestObjectValue;
        生成初始序列
        this.generateInitialSequence(localSequence);
        //初始化bestSequence，刚开始的最优序列为初始序列
        bestSequence = localSequence.clone();
        bestObjectValue = this.getObjectValue(bestSequence);
        迭代优化
        int numOfNotFindBetterSolution = 0;
        for (int iterations = 0; iterations < this.GEN_NUM; iterations++) {
            if (numOfNotFindBetterSolution>this.NUM_OF_NOT_FIND_BETTER_SOLUTION){
                //很长时间都找不到更优解了，说明解已经相对稳定了，牺牲解质量换取更短的求解时间
                break;
            }
            int k = 1;
            boolean isFindBetterSolution = false;
            while (true) {
                ///扰动序列(SHAKING PROCEDURE)
                //扰动最优解产生新解
                if (k == 1) {
                    //随机翻转最优解的一段序列来生成新解
                    localSequence = this.generateNewSequenceByReverseTwoElement(bestSequence);
                } else if (k == 2) {
                    //扰动最优解产生新解
                    localSequence = this.perturbation(bestSequence);
                } else {
                    break;
                }
                ///变邻域下降搜索(VARIABLE NEIGHBORHOOD DESCENT)
                localSequence = this.variableNeighborhoodDescent(localSequence);
                double localObjectValue = this.getObjectValue(localSequence);
                ///更新最优解(tsp问题：优化目标为总距离越短越好)
                if (localObjectValue < bestObjectValue) {
                    bestObjectValue = localObjectValue;
                    bestSequence = localSequence.clone();
                    k = 0;
                    isFindBetterSolution = true;
                    System.out.println("最优目标函数值:" + bestObjectValue);
                    System.out.println("计算时间为：" + (System.currentTimeMillis() - startTime) * 1.0 / 1000 + "s");
                }
                k++;
            }
            if (isFindBetterSolution == true) {
                numOfNotFindBetterSolution = 0;
            } else {
                numOfNotFindBetterSolution++;
            }
        }
        System.out.println("最优目标函数值:" + bestObjectValue);
        System.out.println("最优解对应序列：" + Arrays.toString(bestSequence));
        System.out.println("计算时间为：" + (System.currentTimeMillis() - startTime) * 1.0 / 1000 + "s");
        return bestSequence;
    }
    /**
     * 变邻域下降搜索
     *
     * @param localSequence
     * @return
     */
    private int[] variableNeighborhoodDescent(int[] localSequence) {
        //定义初始解
        double localObjectValue = this.getObjectValue(localSequence);
        //使用领域动作类型
        int l = 1;
        while (true) {
            if (l == 1) {
                //第一种邻域搜索方式：随机交换两个元素的位置
                for (int i = 0; i < SEARCH_NUM; i++) {
                    //找localSequence对应的比较好的邻居序列
                    int[] tempSequence = this.generateNewSequenceBySwapTwoElement(localSequence);
                    double tempObjectValue = this.getObjectValue(tempSequence);
                    //更新localSequence及其对应的解
                    if (tempObjectValue < localObjectValue) {
                        localSequence = tempSequence.clone();
                        localObjectValue = tempObjectValue;
                        //当在本邻域搜索找不出一个比当前解更优的解的时候，我们就跳到下一个邻域继续进行搜索;
                        //当在本邻域搜索找到了一个比当前解更优的解的时候，我们就跳回第一个邻域重新开始搜索
                        l = 0;
                    }
                }
            } else if (l == 2) {
                //第二种邻域搜索方式：将一个元素取出来，插入到另一个位置
                for (int i = 0; i < SEARCH_NUM; i++) {
                    //找localSequence对应的比较好的邻居序列
                    int[] tempSequence = this.insertElementToAnotherPosition(localSequence);
                    double tempObjectValue = this.getObjectValue(tempSequence);
                    //更新localSequence及其对应的解
                    if (tempObjectValue < localObjectValue) {
                        localSequence = tempSequence.clone();
                        localObjectValue = tempObjectValue;
                        //当在本邻域搜索找不出一个比当前解更优的解的时候，我们就跳到下一个邻域继续进行搜索;
                        //当在本邻域搜索找到了一个比当前解更优的解的时候，我们就跳回第一个邻域重新开始搜索
                        l = 0;
                    }
                }
            } else {
                break;
            }
            l++;
        }
        return localSequence;
    }
    /**
     * 通过反转indexI和indexJ之间的元素，产生新的序列
     *
     * @param sequence
     */
    private int[] generateNewSequenceByReverseTwoElement(int[] sequence) {
        //克隆出新序列
        int[] newSequence = sequence.clone();
        int temp;
        Random random = new Random();
        int indexI = random.nextInt(sequence.length);
        int indexJ = random.nextInt(sequence.length);
        while (indexI == indexJ) {
            indexJ = random.nextInt(sequence.length);
        }
        //当indexJ更小时，将indexI和indexJ的数值进行交换
        if (indexJ < indexI) {
            temp = indexI;
            indexI = indexJ;
            indexJ = temp;
        }
        //不但交换indexI和indexJ对应的元素
        while (indexI < indexJ) {
            temp = newSequence[indexI];
            newSequence[indexI] = newSequence[indexJ];
            newSequence[indexJ] = temp;
            indexI++;
            indexJ--;
        }
        return newSequence;
    }
    /**
     * 随机交换两个元素的位置
     *
     * @param sequence
     * @return
     */
    private int[] generateNewSequenceBySwapTwoElement(int[] sequence) {
        int[] sequenceClone = sequence.clone();
        //对序列中的元素进行打乱，即可产生新的序列
        Random random = new Random();
        int i = random.nextInt(sequence.length);
        int j = random.nextInt(sequence.length);
        while (i == j) {
            j = random.nextInt(sequence.length);
        }
        int temp = sequenceClone[i];
        sequenceClone[i] = sequenceClone[j];
        sequenceClone[j] = temp;
        return sequenceClone;
    }
    /**
     * 将index1的元素插入到index2的位置
     *
     * @param sequence 序列
     * @param sequence
     */
    private int[] insertElementToAnotherPosition(int[] sequence) {
        变量声明
        //随机生成两个索引
        Random random = new Random();
        int index1 = random.nextInt(sequence.length);
        int index2 = random.nextInt(sequence.length);
        //判断是前面插到后面还是后面插到前面 type 0:前面插到后面 1：后面插到前面
        int type = index1 < index2 ? 0 : 1;
        //克隆一份序列出来
        int[] sequenceClone = sequence.clone();
        执行插入
        if (type == 0) {
            //--if--将前面的元素插到后面
            //取出要迁移的元素
            int moveElement = sequenceClone[index1];
            //从index1+1开始，将后面的元素分别向前挪动1位
            for (int i = index1 + 1; i <= index2; i++) {
                sequenceClone[i - 1] = sequenceClone[i];
            }
            //将moveElement插入到index2
            sequenceClone[index2] = moveElement;
        } else {
            //--if--将后面的元素插到前面
            //取出要迁移的元素
            int moveElement = sequenceClone[index1];
            //从index1开始，将元素分别向后挪动1位
            for (int i = index1; i > index2; i--) {
                sequenceClone[i] = sequenceClone[i - 1];
            }
            //将moveElement插入到index2
            sequenceClone[index2] = moveElement;
        }
        return sequenceClone;
    }
    /**
     * 扰动序列
     * 通过将bestSequence的元素分为四组，然后改变四个组的组序，获得新序列
     *
     * @param bestSequence
     */
    private int[] perturbation(int[] bestSequence) {
        Random random = new Random();
        int[] newSequence = new int[bestSequence.length];
        获取五个index，这五个index将bestSequence划分为四组(并非均分)
        //this.cityNum - 2的原因是：indexArr[0]和indexArr[4]都已经确定
        int elementNumInOneGroup = (this.CITY_NUM - 2) / 3;
        int[] indexArr = new int[5];
        indexArr[0] = 0;
        indexArr[1] = random.nextInt(elementNumInOneGroup) + 1;
        indexArr[2] = random.nextInt(elementNumInOneGroup) + elementNumInOneGroup + 1;
        indexArr[3] = random.nextInt(elementNumInOneGroup) + elementNumInOneGroup * 2 + 1;
        indexArr[4] = this.CITY_NUM;
        将组别[0,1,2,3]对应的元素赋值给newSequence
        ///将组序打乱
        List<Integer> groupCodeList = new ArrayList<>();
        //将[0,1,2,3]赋值给集合
        Collections.addAll(groupCodeList, 0, 1, 2, 3);
        //随机打乱
        Collections.shuffle(groupCodeList);
        ///赋值
        int index = 0;
        for (int i = 0; i < groupCodeList.size(); i++) {
            for (int j = indexArr[groupCodeList.get(i)]; j < indexArr[groupCodeList.get(i) + 1]; j++) {
                newSequence[index] = bestSequence[j];
                index++;
            }
        }
        return newSequence;
    }
    /**
     * 生成初始序列
     */
    private void generateInitialSequence(int[] sequence) {
        HashSet<Integer> sequenceSet = new HashSet<>();
        for (int i = 1; i < sequence.length; i++) {
            sequenceSet.add(i);
        }
        //贪婪算法获取初始序列，从城市0开始旅行，即城市0为起点城市
        sequence[0] = 0;
        //每次获取离当前城市最近的城市，并加入到sequence
        for (int i = 1; i < sequence.length; i++) {
            //寻找离i-1城市最近的城市，即确定第i个城市是哪个
            double smallDistance = Double.MAX_VALUE;
            int curCity = 0;
            for (Integer j : sequenceSet) {
                if (this.distanceMatrix[sequence[i - 1]][j] < smallDistance && j != sequence[i - 1]) {
                    smallDistance = this.distanceMatrix[sequence[i - 1]][j];
                    curCity = j;
                }
            }
            sequence[i] = curCity;
            sequenceSet.remove(curCity);
        }
      /*  for (int i = 0; i < sequence.length; i++) {
            sequence[i] = i;
        }*/
    }
    /**
     * 根据当前序列获取目标函数值
     *
     * @param sequence
     * @return
     */
    private double getObjectValue(int[] sequence) {
        double objectValue = 0;
        //计算从第0个城市到最后一个城市的路程
        for (int i = 0; i < sequence.length - 1; i++) {
            objectValue += this.distanceMatrix[sequence[i]][sequence[i + 1]];
        }
        //计算最后一个城市到第0个城市的路程
        objectValue += this.distanceMatrix[sequence[0]][sequence[sequence.length - 1]];
        return objectValue;
    }
}

package com.dam.heuristic.algorithm.vns.dam;
import com.dam.heuristic.algorithm.vns.dam.v1.VnsApiV1;
import com.dam.heuristic.algorithm.vns.dam.v2.VnsApiV2;
import java.io.File;
import java.io.FileInputStream;
public class VnsMainRun {
    public static void main(String[] args) throws Exception {
        声明变量
        //距离矩阵，可以直接获取任意两个编号城市的距离
        double[][] distanceMatrix;
        //存储每个城市对应的x,y坐标
        double[][] cityPositionArr;
        读取数据
        String data = read(new File("src/main/java/com/data/tsp/att48.txt"), "GBK");
        String[] cityDataArr = data.split("\n");
        //初始化数组
        distanceMatrix = new double[cityDataArr.length][cityDataArr.length];
        cityPositionArr = new double[cityDataArr.length][2];
        for (int i = 0; i < cityDataArr.length; i++) {
            String[] city1Arr = cityDataArr[i].split(" ");
            cityPositionArr[i][0] = Double.valueOf(city1Arr[1]);
            cityPositionArr[i][1] = Double.valueOf(city1Arr[2]);
            int cityOne = Integer.valueOf(city1Arr[0]);
            for (int j = 0; j < i; j++) {
                String[] city2Arr = cityDataArr[j].split(" ");
                int cityTwo = Integer.valueOf(city2Arr[0]);
                if (cityOne == cityTwo) {
                    distanceMatrix[cityOne - 1][cityTwo - 1] = 0;
                } else {
                    distanceMatrix[cityOne - 1][cityTwo - 1] = getDistance(Double.valueOf(city1Arr[1]), Double.valueOf(city1Arr[2]), Double.valueOf(city2Arr[1]), Double.valueOf(city2Arr[2]));
                    //对称赋值
                    distanceMatrix[cityTwo - 1][cityOne - 1] = distanceMatrix[cityOne - 1][cityTwo - 1];
                }
            }
        }
/*        VnsApiV1 vnsApiV1 = new VnsApiV1(1000, 40, 500, 50, distanceMatrix);
        vnsApiV1.solve();*/
        VnsApiV2 vnsApiV2 = new VnsApiV2(3000, 100, 100000, distanceMatrix);
        vnsApiV2.solve();
    }
    /**
     * 给定两个城市坐标，获取两个城市的直线距离
     *
     * @param x1
     * @param y1
     * @param x2
     * @param y2
     * @return
     */
    private static double getDistance(double x1, double y1, double x2, double y2) {
        return Math.sqrt((Math.pow((x1 - x2), 2) + Math.pow((y1 - y2), 2)) / 10);
    }
    private static String read(File f, String charset) throws Exception {
        FileInputStream fstream = new FileInputStream(f);
        try {
            int fileSize = (int) f.length();
            if (fileSize > 1024 * 512) {
                throw new Exception("File too large to read! size=" + fileSize);
            }
            byte[] buffer = new byte[fileSize];
            fstream.read(buffer);
            return new String(buffer, charset);
        } finally {
            try {
                fstream.close();
            } catch (Exception e) {
            }
        }
    }
}