2024-07-23 13:26:16 192 0

AI与数学

有1000个产品，每个产品有长宽高体积属性，从业务上看，长宽高相差不超过指定数的产品，可以认为是相似产品。

我们计算其欧几里得距离：当距离小于阈值时，认为相似。

不过时间复杂度过高。对于少量的产品，还是能够计算的。

import java.util.ArrayList;
import java.util.List;

class Point {
    double x, y, z;

    Point(double x, double y, double z) {
        this.x = x;
        this.y = y;
        this.z = z;
    }

    double distance(Point other) {
        return Math.sqrt(Math.pow(this.x - other.x, 2) +
                         Math.pow(this.y - other.y, 2) +
                         Math.pow(this.z - other.z, 2));
    }
}

public class NearestPointsFinder {
    public static List<List<Point>> findClosePoints(List<Point> points, double threshold) {
        List<List<Point>> closePointsGroups = new ArrayList<>();

        for (int i = 0; i < points.size(); i++) {
            List<Point> closePoints = new ArrayList<>();
            Point currentPoint = points.get(i);
            closePoints.add(currentPoint);

            for (int j = 0; j < points.size(); j++) {
                if (i != j) {
                    Point otherPoint = points.get(j);
                    if (currentPoint.distance(otherPoint) < threshold) {
                        closePoints.add(otherPoint);
                    }
                }
            }

            // 确保不会将相同的组加入列表
            if (!closePoints.isEmpty() && !closePointsGroups.contains(closePoints)) {
                closePointsGroups.add(closePoints);
            }
        }

        return closePointsGroups;
    }

    public static void main(String[] args) {
        List<Point> points = new ArrayList<>();
        points.add(new Point(1, 2, 3));
        points.add(new Point(1.1, 2.1, 3.1));
        points.add(new Point(5, 5, 5));
        points.add(new Point(5.2, 5.2, 5.2));

        double threshold = 0.5;  // 距离阈值
        List<List<Point>> closePoints = findClosePoints(points, threshold);

        // 打印结果
        for (List<Point> group : closePoints) {
            System.out.print("Close points: ");
            for (Point point : group) {
                System.out.print("(" + point.x + ", " + point.y + ", " + point.z + ") ");
            }
            System.out.println();
        }
    }
}