用c++写一个一维AGNES聚类方法

下面是一个使用C++编写的一维AGNES聚类方法的示例代码：

#include <iostream>
#include <vector>
#include <cmath>

using namespace std;

// 计算欧几里得距离
double euclidean_distance(double a, double b) {
    return sqrt(pow(a - b, 2));
}

// 计算两个簇之间的距离
double cluster_distance(vector<double>& cluster1, vector<double>& cluster2) {
    double min_distance = INFINITY;
    for (double& a : cluster1) {
        for (double& b : cluster2) {
            double distance = euclidean_distance(a, b);
            if (distance < min_distance) {
                min_distance = distance;
            }
        }
    }
    return min_distance;
}

// 将两个簇合并
void merge_clusters(vector<vector<double>>& clusters, int index1, int index2) {
    // 将index2中的元素添加到index1中
    for (double& a : clusters[index2]) {
        clusters[index1].push_back(a);
    }
    // 删除index2
    clusters.erase(clusters.begin() + index2);
}

// AGNES聚类
vector<vector<double>> agnes_clustering(vector<double>& data, int k) {
    // 初始化每个数据点为一个簇
    vector<vector<double>> clusters;
    for (double& a : data) {
        vector<double> cluster;
        cluster.push_back(a);
        clusters.push_back(cluster);
    }

    // 逐步合并簇
    while (clusters.size() > k) {
        int min_i = 0, min_j = 1;
        double min_distance = cluster_distance(clusters[0], clusters[1]);
        // 找到距离最近的两个簇
        for (int i = 0; i < clusters.size(); i++) {
            for (int j = i + 1; j < clusters.size(); j++) {
                double distance = cluster_distance(clusters[i], clusters[j]);
                if (distance < min_distance) {
                    min_distance = distance;
                    min_i = i;
                    min_j = j;
                }
            }
        }
        // 合并最近的两个簇
        merge_clusters(clusters, min_i, min_j);
    }

    return clusters;
}

int main() {
    vector<double> data = { 1, 2, 4, 10, 11, 13, 15, 16, 17, 18 };
    int k = 3;
    vector<vector<double>> clusters = agnes_clustering(data, k);

    // 输出聚类结果
    for (int i = 0; i < clusters.size(); i++) {
        cout << "Cluster " << i + 1 << ": ";
        for (double& a : clusters[i]) {
            cout << a << " ";
        }
        cout << endl;
    }

    return 0;
}

该示例代码实现了一维数据的AGNES聚类方法，并可以指定聚成的簇数。输入数据为一维数组，输出结果为聚类后的簇。