编程练习：Transmitters

来源：互联网发布：绝地求生优化太差编辑：程序博客网时间：2024/06/14 21:36

为何保持编程的兴趣，还是找一些代码来写

看了 http://poj.org/problem?id=1106，分析思路如下：

1）把坐标系原点定位为圆心，把其他点转化为极坐标

2）从第一个点开始，逐个查找满足所有落在下面区域内的点：此点到原点为起始边，半径为参数所给的半圆围成区域

3）所有点都扫描后给出最大覆盖的点数

package com.pnp.hello;import java.awt.Color;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.geom.Arc2D;import javax.swing.JFrame;public class Hello {static class My extends JFrame { double circle_x = 250; double circle_y = 250; double circle_r = 35;double[][] in_points = new double[][]{{250, 280},{230, 270},{270, 270},{240, 230},{260, 230},{240, 290},{260, 290}};double[][] points = new double[in_points.length][2];double angles[] = new double[points.length];double dists[] =  new double[points.length];int max_count=0; // max point countint begin_index=-1; // the begin point of half circleint draw_index=0; // for drawing animationvoid cal () {// trans coordinate to polar coordinatefor ( int i=0; i < points.length; i++ ) {points[i][0] = in_points[i][0] - circle_x;points[i][1] = in_points[i][1] - circle_y;angles[i] = Math.atan2(points[i][1], points[i][0]);dists[i] = Math.sqrt( points[i][0] * points[i][0] + points[i][1] * points[i][1] );}// countfor ( int i=0; i < points.length; i++ ) {int count =0;for ( int j=0; j < points.length; j++) {double begin_a = angles[i];double end_a = begin_a + Math.PI;if ( angles[j] >= begin_a  &&  angles[j] <= end_a && dists[j] < circle_r)count++;}if ( count > max_count ) {max_count = count;begin_index = i;}// for animations effectdraw_index = i;this.repaint();try {Thread.sleep(5000);} catch (InterruptedException e) {e.printStackTrace();}}this.repaint();draw_index = begin_index;System.out.printf("max_count: " + max_count  + "  begin_index: " + begin_index);}public void paint(Graphics g) {g.clearRect(0, 0, 500, 500);double ag = angles[draw_index];Arc2D arc = new Arc2D.Double(circle_x-circle_r, circle_y-circle_r, circle_r*2, circle_r*2, ag/Math.PI * 180, 180 , Arc2D.PIE);Graphics2D g2d = (Graphics2D) g;g2d.fill(arc);g.setColor(Color.RED);for ( int i=0; i < in_points.length; i++ ) {g.drawLine((int)in_points[i][0],(int)in_points[i][1] ,(int)in_points[i][0] + 1 , (int)in_points[i][1] +1 );//g.drawLine((int)circle_x-circle_r,(int)circle_y,(int)circle_x + circle_r , (int)circle_y );}}}public static void main(String[] args) {My frame = new Hello.My();frame.setTitle("half circle cover points");frame.setBounds(0, 0, 500, 500);frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);frame.setVisible(true);frame.cal();}}

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