Snapchat-vehicle through radar Area

There is a path, and the two sides can be imagined as Y = 0 and y = 1. Now we will give you a list of radar, where each radar is (x coordinate, Y coordinate, and radiation radius ). Ask if a car can pass this road.

 

Code statement:

 1     static class Radar { 2         double x; 3         double y; 4         double r; 5         public Radar(double x, double y, double r) { 6             this.x = x; 7             this.y = y; 8             this.r = r; 9         }10     }11     12     class Area {13         List<Radar> radars;14         double upperbound;15         double lowerbound;16         17         public Area() {18             radars = new ArrayList<Radar>();19             upperbound = 0;20             lowerbound = 1;21         }22         23         private boolean canMerge(Radar r1, Radar r2) {24             return Math.pow(r1.r + r2.r, 2) >= Math.pow(r1.x - r2.x, 2) + Math.pow(r1.y - r2.y, 2);25         }26         27         private boolean merge(Radar r) {28             for(Radar radar: radars) {29                 if(canMerge(r, radar)) {30                     upperbound = Math.max(upperbound, r.x + r.r);31                     lowerbound = Math.min(lowerbound, r.y - r.r);32                     radars.add(r);33                     return true;34                 }35             }36             return false;37         }38         39         private boolean cannotPass() {40             return upperbound >= 1 && lowerbound <= 0;41         }42     }43     44     45     public boolean canCarPass(List<Radar> radars) {46         List<Area> area = new ArrayList<Area>();47         for(Radar radar: radars) {48             boolean merged = false;49             for(Area a: area) {50                 merged = a.merge(radar);51                 if(merged) {52                     break;53                 }54             }55             if(!merged) {56                 Area a = new Area();57                 a.radars.add(radar);58                 area.add(a);59             }60         }61         for(Area a : area) {62             if(a.cannotPass()) {63                 return false;64             }65         }66         return true;67     }68     69     public static void main(String[] args) {70         RadarDetect rd = new RadarDetect();71         //List<Radar> radars = Arrays.asList(new Radar(1, 0.5, 0.49), new Radar(3, 1.5, 1), new Radar(3, 0.4, 0.3));72         List<Radar> radars = Arrays.asList(new Radar(1, 0, 1.5), new Radar(3, 1, 1.5));73         System.out.println(rd.canCarPass(radars));74     }

 

Snapchat-vehicle through radar Area