public void initSubproblems() { // initVisibility first
int i;
i = reflexIter();
if (i == 0) {
setAfter(i);
i = reflexNext(i);
}
if (i == 1) {
subD.setWeight(0, 1, 0);
setAfter(i);
i = reflexNext(i);
}
while (i < n - 2) {
setBefore(i);
setAfter(i);
i = reflexNext(i);
}
if (i == n - 2) {
setBefore(i);
subD.setWeight(i, i + 1, 0);
i = reflexNext(i);
}
if (i == n - 1) {
setBefore(i);
}
}
/*
* We have a new solution for subprob a,b with weight w, using i,j. If it is
* better than previous solutions, we update. We assume that a<b and i < j.
*/
public void update(int a, int b, int w, int i, int j) {
// System.out.print("update("+a+","+b+" w:"+w+" "+i+","+j+")");
int ow = subD.weight(a, b);
if (w <= ow) {
PairDeque pair = subD.pairs(a, b);
if (w < ow) {
pair.flush();
subD.setWeight(a, b, w);
}
pair.pushNarrow(i, j);
}
}
public void typeB(int i, int j, int k) {
/* k reflex, i not. */
// System.out.print("\nB "+i+","+j+","+k+":");
if (!visible(j, k)) return;
int top = j;
int w = subD.weight(j, k);
if (j - i > 1) {
if (!visible(i, j)) return;
w += subD.weight(i, j) + 1;
}
if (k - j > 1) { // check if must use jk, too.
PairDeque pair = subD.pairs(j, k);
if (!Point.right(sp.p(i), sp.p(j), sp.p(pair.aF()))) {
while (pair.more1() && !Point.right(sp.p(i), sp.p(j), sp.p(pair.underaF()))) pair.pop();
if ((!pair.empty()) && !Point.left(sp.p(i), sp.p(k), sp.p(pair.bF()))) top = pair.bF();
else w++; // yes, use jk. top=j already
} else w++; // yes, use jk. top=j already
}
update(i, k, w, j, top);
}
public void initVisibility() { // initReflex() first
// if (animating())
// animGraphics.setColor(Color.yellow);
VisPoly vp = new VisPoly(sp);
for (int i = reflexIter(); i < n; i = reflexNext(i)) {
vp.build(i);
while (!vp.empty()) {
int j = vp.popVisible() % n;
if (j < i) subD.setWeight(j, i, INFINITY);
else subD.setWeight(i, j, INFINITY);
// if (animating())
// animGraphics.drawLine(sp.p(i).x(), sp.p(i).y(),
// sp.p(j).x(), sp.p(j).y());
}
}
// if (animating()) {
// animGraphics.setColor(Color.blue);
// try { Thread.sleep(DELAY);
// } catch(InterruptedException e) {
// }
// }
}
public void typeA(int i, int j, int k) {
/* i reflex; use jk */
// System.out.print("\nA "+i+","+j+","+k+":");
// assert(reflex(i), "non reflex i in typeA("+i+","+j+","+k+")");
// assert(k-i > 1, "too small in typeA("+i+","+j+","+k+")");
if (!visible(i, j)) return;
int top = j;
int w = subD.weight(i, j);
if (k - j > 1) {
if (!visible(j, k)) return;
w += subD.weight(j, k) + 1;
}
if (j - i > 1) { // check if must use ij, too.
PairDeque pair = subD.pairs(i, j);
if (!Point.left(sp.p(k), sp.p(j), sp.p(pair.bB()))) {
while (pair.more1B() && !Point.left(sp.p(k), sp.p(j), sp.p(pair.underbB()))) pair.popB();
if ((!pair.emptyB()) && !Point.right(sp.p(k), sp.p(i), sp.p(pair.aB()))) top = pair.aB();
else w++; // yes, need ij. top = j already
} else w++; // yes, need ij. top = j already
}
update(i, k, w, top, j);
}
public void recoverSolution(int i, int k) {
int j;
if (guard-- < 0) {
// System.out.println("Can't recover" + i + "," + k);
return;
}
if (k - i <= 1) return;
PairDeque pair = subD.pairs(i, k);
if (reflex(i)) {
j = pair.bB();
recoverSolution(j, k);
if (j - i > 1) {
if (pair.aB() != pair.bB()) {
PairDeque pd = subD.pairs(i, j);
pd.restore();
while ((!pd.emptyB()) && pair.aB() != pd.aB()) pd.popB();
// assert(!pd.emptyB(),
// "emptied pd "+i+","+j+","+k+" "+pair.toString());
}
recoverSolution(i, j);
}
} else {
j = pair.aF();
recoverSolution(i, j);
if (k - j > 1) {
if (pair.aF() != pair.bF()) {
PairDeque pd = subD.pairs(j, k);
pd.restore();
while ((!pd.empty()) && pair.bF() != pd.bF()) pd.pop();
// assert(!pd.empty(),
// "emptied pd "+i+","+j+","+k+" "+pair.toString());
}
recoverSolution(j, k);
}
}
}
private void drawHelper(Graphics g, int i, int k) {
int j;
boolean ijreal = true, jkreal = true;
if (k - i <= 1) return;
PairDeque pair = subD.pairs(i, k);
if (reflex(i)) {
j = pair.bB();
ijreal = (pair.aB() == pair.bB());
} else {
j = pair.aF();
jkreal = (pair.bF() == pair.aF());
}
if (ijreal) {
drawDiagonal(g, i, j);
}
// else if (label) {
// g.setColor(Color.orange);
// drawDiagonal(g, label, i, j);
// g.setColor(Color.blue);
// }
if (jkreal) {
drawDiagonal(g, j, k);
}
// else if (label) {
// g.setColor(Color.orange);
// drawDiagonal(g, label, j, k);
// g.setColor(Color.blue);
// }
if (guard-- < 0) {
// System.out.println("Infinite Loop drawing" + i + "," + k);
return;
}
drawHelper(g, i, j);
drawHelper(g, j, k);
}
public boolean visible(int i, int j) {
return subD.weight(i, j) < BAD;
}
public void initPairs(int i, int k) {
subD.init(i, k);
}
private void setBefore(int i) { // i reflex
// assert(reflex(i), "non reflex i in setAfter("+i+")");
subD.setWeight(i - 1, i, 0);
if (visible(i - 2, i)) subD.init(i - 2, i, 0, i - 1, i - 1);
}
private void setAfter(int i) { // i reflex
// assert(reflex(i), "non reflex i in setAfter("+i+")");
subD.setWeight(i, i + 1, 0);
if (visible(i, i + 2)) subD.init(i, i + 2, 0, i + 1, i + 1);
}