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Author: javaarchive

cowjump.java

@@ -1,12 +1,73 @@
 import java.io.*;
 import java.util.*;
 public class cowjump {
+	public static int pointYCompare(Point p1, Point p2) {
+		// Compare points
+		// Check if p2 is above, below, or next to p1
+		System.out.println("pointycompare(("+p1.x+","+p1.y+"),("+p2.x+","+p2.y+")");
+		if(p1.y == p2.y) {
+			System.out.println("output: 0"); // Same Y
+			return 0;
+		}
+		if(p2.y < p1.y) {
+			System.out.println("output: -1"); // below
+			return -1;
+		}
+		if(p2.y > p1.y) {
+			System.out.println("output: 1"); // above
+			return 1;
+		}
+		System.out.println("NONE OF THE ABOVE"); // This code should never run, but just keeping this to prevent syntax errors
+		return -9999999;
+	}
+	public static int linesCompare(LineSegement m, LineSegement l) {
+		System.out.println("Checking if line ("+m.a.x+","+m.a.y+")--"+"("+m.b.x+","+m.b.y+")" + " intersects with " + "("+l.a.x+","+l.a.y+")--"+"("+l.b.x+","+l.b.y+")");
+		return pointYCompare(m.a, l.a) * pointYCompare(m.b, l.b);
+	}
 	public static void testIntersections() {
 		assert Point.intersection(new Point(0,0), new Point(2,9), new Point(0,1), new Point(6,1))== true; 
-		assert Point.intersection(new Point(0,0), new Point(1,1), new Point(3,3), new Point(3,12))== false; 
+		//assert Point.intersection(new Point(0,0), new Point(1,1), new Point(3,3), new Point(3,12))== false; 
+		assert linesCompare(new LineSegement(new Point(0,0), new Point(2,3)),new LineSegement(new Point(0,3),new Point(9,1))) == -1;
 		System.out.println("All Tests OK!");
 	}
+	public static boolean sweepCheck(LineSegement s,Point[][] input) {
+		for(int i = 0; i < input.length; i ++) {
+			System.out.println("Checking line "+i);
+			if(input[i][0] == null || input[i][1] == null) {
+				System.out.println("End of segments");
+				break;
+			}
+			System.out.println("Checking "+s.a.x+" - "+input[i][0].x + " - "+s.b.x);
+			boolean firstWithinLine = (s.a.x <= input[i][0].x && s.b.x >= input[i][0].x);
+			System.out.println("firstWithinLine = "+firstWithinLine);
+			//|| (s.a.y <= input[i][0].y && s.b.y >= input[i][0].y);
+			if(firstWithinLine) {
+				// TODO check line cross logic
+				if(linesCompare(s,new LineSegement(input[i][0], input[i][1])) == -1) {
+					System.out.println("Intersect!");
+					return true;
+				}else {
+					System.out.println("No Intersection!");
+				}
+				continue; // Both statements may be true
+			}
+			boolean secondWithinLine = (s.a.x <= input[i][1].x && s.b.x >= input[i][1].x);
+			//|| (s.a.y <= input[i][0].y && s.b.y >= input[i][0].y);
+			if(secondWithinLine) {
+				// TODO check line cross logic
+				if(linesCompare(s,new LineSegement(input[i][0], input[i][1])) == -1) {
+					System.out.println("Intersect!");
+					return true;
+				}else {
+					System.out.println("No Intersection!");
+				}
+			}
+			
+		}
+		return false;
+	}
 	public static void main(String[] args) throws IOException{
+		testIntersections();
 		// TODO Auto-generated method stub
 		//testIntersections();
 		BufferedReader f = new BufferedReader(new FileReader("cowjump.in"));
@@ -15,17 +76,29 @@ public static void main(String[] args) throws IOException{
 		//System.out.println(input[0][0]);
 		for(int i = 0; i < N; i ++) {
 			StringTokenizer st = new StringTokenizer(f.readLine());
-			input[i][0] = new Point(Integer.parseInt(st.nextToken()), Integer.parseInt(st.nextToken()));
-			input[i][1] = new Point(Integer.parseInt(st.nextToken()), Integer.parseInt(st.nextToken()));
-			for(int j = 0; j < i; j ++) {
+			Point a = new Point(Integer.parseInt(st.nextToken()), Integer.parseInt(st.nextToken()));
+			Point b = new Point(Integer.parseInt(st.nextToken()), Integer.parseInt(st.nextToken()));
+			if(a.x > b.x) {
+				System.out.println(sweepCheck(
+						new LineSegement(b,a),
+						input));
+			}else {
+			System.out.println(sweepCheck(
+					new LineSegement(a,b),
+					input));
+			}
+			input[i][0] = a;
+			input[i][1] = b;
+			/*for(int j = 0; j < i; j ++) {
 				if(Point.intersection(input[j][0], input[j][1], input[i][0], input[i][1])) {
 					PrintWriter pw = new PrintWriter("cowjump.out");
 					pw.println(i+1);
 					pw.close();
 					System.exit(0);
 				}
-			}
+			}*/
 		}
+		
 	}
 
 }
@@ -56,4 +129,24 @@ static boolean intersection(Point a, Point b,Point c, Point d) {
 		}
 		return false;
 	}
+}
+
+class LineSegement {
+	Point a,b;
+	public LineSegement(Point a,Point b) {
+		if(a.x > b.x) {
+			this.a = b;
+			this.b = a;
+		}else {
+		this.a = a;
+		this.b = b;
+		}
+	}
+	public double atX(int x) {
+		if(this.a.y == this.b.y) { // Straight
+			return this.a.y;
+		}else {
+			return this.a.y * (x/this.a.x);
+		}
+	}
 }