源码一JarvisMarchjava
package nvex;
import static javalangMathabs;
import javautilIterator;
import javautilLinkedList;
import javautilList;
public class JarvisMarch {
private int count;
public int getCount() {
return count;
}
public void setCount(int count) {
unt = count;
}
private static int MAX_ANGLE = ;
private double currentMinAngle = ;
private List<Point> hullPointList;
private List<Integer> indexList;
private PointFactory pf;
private Point[] ps;
public Point[] getPs() {
return ps;
}
private int firstIndex;
public int getFirstIndex() {
return firstIndex;
}
public JarvisMarch() {
this();
}
public JarvisMarch(int count) {
pf = PointFactorygetInstance(count);
initialize();
}
public JarvisMarch(int[] x int[] y) {
pf = PointFactorygetInstance(x y);
initialize();
}
private void initialize() {
hullPointList = new LinkedList<Point>();
indexList = new LinkedList<Integer>();
firstIndex = pfgetFirstIndex();
ps = pfgetPoints();
addToHull(firstIndex);
}
private void addToHull(int index) {
indexListadd(index);
hullPointListadd(ps[index]);
}
public int calculateHull() {
for (int i = getNextIndex(firstIndex); i != firstIndex; i = getNextIndex(i)) {
addToHull(i);
}
showHullPoints();
return ;
}
private void showHullPoints() {
Iterator<Point> itPoint = erator();
Iterator<Integer> itIndex = erator();
Point p;
int i;
int index = ;
Systemoutprintln(The hull points is: > );
while (itPointhasNext()) {
i = itIndexnext();
p = itPointnext();
Systemoutprint(i + :( + pgetX() + + pgetY() + ) );
index++;
if (index % == )
Systemoutprintln();
}
Systemoutprintln();
Systemoutprintln(****************************************************************);
Systemoutprintln(The count of all hull points is + index);
}
public int getNextIndex(int currentIndex) {
double minAngle = MAX_ANGLE;
double pseudoAngle;
int minIndex = ;
for (int i = ; i < pslength; i++) {
if (i != currentIndex) {
pseudoAngle = getPseudoAngle(ps[i]getX() ps[currentIndex]getX()
ps[i]getY() ps[currentIndex]getY());
if (pseudoAngle >= currentMinAngle && pseudoAngle < minAngle) {
minAngle = pseudoAngle;
minIndex = i;
} else if (pseudoAngle == minAngle){
if((abs(ps[i]getX() ps[currentIndex]getX()) >
abs(ps[minIndex]getX() ps[currentIndex]getX()))
|| (abs(ps[i]getY() ps[currentIndex]getY()) >
abs(ps[minIndex]getY() ps[currentIndex]getY()))){
minIndex = i;
}
}
}
}
currentMinAngle = minAngle;
return minIndex;
}
public double getPseudoAngle(double dx double dy) {
if (dx > && dy >= )
return dy / (dx + dy);
if (dx <= && dy > )
return + (abs(dx) / (abs(dx) + dy));
if (dx < && dy <= )
return + (dy / (dx + dy));
if (dx >= && dy < )
return + (dx / (dx + abs(dy)));
throw new Error(Impossible);
}
}
源码二Pointjava
package nvex;
public class Point {
// 定义点的xy坐标之所以是int类型是为了日后可以在计算机屏幕上进行可视化
private int x;
private int y;
// xy的get方法
public int getX() {
return x;
}
public int getY() {
return y;
}
// 定义点到屏幕边缘的距离
private static double PADDING = ;
// 点在屏幕中的范围
private static double POINT_RANGE = ( PADDING * );
// 默认构造方法产生随机点
public Point() {
thisx = (int) ((Mathrandom() * POINT_RANGE) + PADDING);
thisy = (int) ((Mathrandom() * POINT_RANGE) + PADDING);
}
// 带参构造方法可以实现手动输入固定点
public Point(int x int y) {
thisx = x;
thisy = y;
}
// 覆写hashCode()和equals()方法实现比较和Hash
@Override
public int hashCode() {
final int prime = ;
int result = ;
result = prime * result + x;
result = prime * result + y;
return result;
}
@Override
public boolean equals(Object obj) {
Point other = (Point) obj;
if ((x == otherx) && (y == othery))
return true;
return false;
}
}
源码三PointFactoryjava
package nvex;
public class PointFactory {
/**
* 单例模式大批量产生Point也可以手动产生Point
*/
private Point[] points = null;
private int newIndex;
private int firstIndex = ;
public Point[] getPoints() {
return points;
}
public int getFirstIndex() {
return firstIndex;
}
public static PointFactory getInstance() {
return new PointFactory();
}
public static PointFactory getInstance(int count) {
return new PointFactory(count);
}
public static PointFactory getInstance(int[] x int[] y) {
return new PointFactory(x y);
}
private PointFactory() {
this();
}
private PointFactory(int count) {
points = new Point[count];
for (int i = ; i < count; i++) {
points[i] = new Point();
newIndex = i;
validatePoints();
}
firstIndex = getFirstPoint();
}
public PointFactory(int[] x int[] y) {
points = new Point[ylength];
for (int i = ; i < ylength; i++) {
points[i] = new Point(x[i] y[i]);
}
firstIndex = getFirstPoint();
}
private void validatePoints() {
for(int i = ; i < newIndex; i++) {
if(points[i]equals(points[newIndex])) {
points[newIndex] = new Point();
validatePoints();
}
}
}
public int getFirstPoint() {
int minIndex = ;
for (int i = ; i < pointslength; i++) {
if (points[i]getY() < points[minIndex]getY()) {
minIndex = i;
} else if ((points[i]getY() == points[minIndex]getY())
&& (points[i]getX() < points[minIndex]getX())) {
minIndex = i;
}
}
return minIndex;
}
}
源码四Testjava（主函数）
package nvex;
public class Test {
public static void main(String[] args) {
long start = SystemcurrentTimeMillis();
JarvisMarch j = new JarvisMarch();
Point[] points = jgetPs();
int firstIndex = jgetFirstIndex();
// for (int i = ; i < pointslength; i++) {
// Systemoutprint(i + :( + points[i]getX() + + points[i]getY() + ) );
// if((i+) % == ) {
// Systemoutprintln();
// }
// }
// Systemoutprintln();
// Systemoutprintln(*****************************************************************);
Systemoutprintln(the first point is: + firstIndex + :( +
points[firstIndex]getX() + + points[firstIndex]getY() + ));
Systemoutprintln(*****************************************************************);
jcalculateHull();
Systemoutprintln(The total running time is + (SystemcurrentTimeMillis() start) + millis);
}
}
