[数据结构与算法]day52

1.原程序为重复n次，并将已经输出的点筛去，以筛选出最近的n个点

为了减小计算量，以插入排序将所有值排序，则可以直接在序列中选择最小的n个点

    /**
     * *******************************
     * Compute the nearest k neighbors. Select one neighbor in each scan. In
     * fact we can only once. You may implement it by yourself.
     *
     * @param paraCurrent current instance. We are comparing it with all others.
     * @return the indices of the nearest instances.
     * *******************************
     */
    public int[] computeNearests(int paraCurrent) {
        int[] resultNearests = new int[numNeighbors];
        boolean[] tempSelected = new boolean[trainingSet.length];
        double tempDistance;
        double tempMinimalDistance;
        int tempMinimalIndex = 0;
        int j;
        int[] searchTable = new int[trainingSet.length];

        double[] distance = new double[trainingSet.length];

        //计算所有点的distance
        for (int i = 0; i <  trainingSet.length; i++) {
            searchTable[i] = i;
            distance[i] = distance(paraCurrent, trainingSet[i]);
        }//of for i
        //对distance进行插入排序，同时设置searchTable跟踪该distance原位置
        for (int i = 1; i <  trainingSet.length; i++) {
            tempDistance = distance[i];

            for (j = i - 1;  j >= 0 && distance[j] > tempDistance;j--) {
                distance[j + 1] = distance[j];
                searchTable[j + 1] = searchTable[j];
            }//of for j

            distance[j + 1] = tempDistance;
            searchTable[j + 1] = i;
        }//of for i

        //输出n个最小值
        for (int i = 0; i < numNeighbors; i++) {
            resultNearests[i] = trainingSet[searchTable[i]];
        }//of for i

        System.out.println("The nearest of " + paraCurrent + " are: " + Arrays.toString(resultNearests));
        return resultNearests;
    }//of computeNearests

2.setDistanceMeasure

 public void setDistanceMeasure(int distanceMeasure) {
        this.distanceMeasure = distanceMeasure;
    }//setDistanceMeasure

3.setNumNeighbors

    public void setNumNeighbors(int numNeighbors) {
        this.numNeighbors = numNeighbors;
    }//setDistanceMeasure