/*
* a common ancestor of v and w that participates in a shortest ancestral
* path; -1 if no such path
*/
public int ancestor(int v, int w) {
if ((!checkVertexInBound(v)) || (!checkVertexInBound(w)))
throw new java.lang.IndexOutOfBoundsException();
BreadthFirstDirectedPaths bfdDirPaths1 = new BreadthFirstDirectedPaths(copyG, v);
BreadthFirstDirectedPaths bfdDirPaths2 = new BreadthFirstDirectedPaths(copyG, w);
int minLength = Integer.MAX_VALUE;
int commAncestor = Integer.MAX_VALUE;
for (int vrtx = 0; vrtx < copyG.V(); vrtx++) {
int dist1 = bfdDirPaths1.distTo(vrtx);
int dist2 = bfdDirPaths2.distTo(vrtx);
int dist = dist1 + dist2;
if (Integer.MAX_VALUE != dist1 && Integer.MAX_VALUE != dist2 && dist < minLength) {
minLength = dist;
commAncestor = vrtx;
}
}
if (Integer.MAX_VALUE == minLength) {
commAncestor = -1;
}
return commAncestor;
}
/*
* length of shortest ancestral path between any vertex in v and any vertex
* in w; -1 if no such path
*/
public int length(Iterable<Integer> v, Iterable<Integer> w) {
for (int vrtx : v) {
if (!checkVertexInBound(vrtx)) throw new java.lang.IndexOutOfBoundsException();
}
for (int vrtx : w) {
if (!checkVertexInBound(vrtx)) throw new java.lang.IndexOutOfBoundsException();
}
BreadthFirstDirectedPaths bfdDirPaths1 = new BreadthFirstDirectedPaths(copyG, v);
BreadthFirstDirectedPaths bfdDirPaths2 = new BreadthFirstDirectedPaths(copyG, w);
int minPath = Integer.MAX_VALUE;
for (int vrtx = 0; vrtx < copyG.V(); vrtx++) {
int dist1 = bfdDirPaths1.distTo(vrtx);
int dist2 = bfdDirPaths2.distTo(vrtx);
int dist = dist1 + dist2;
if (Integer.MAX_VALUE != dist1 && Integer.MAX_VALUE != dist2 && dist < minPath) {
minPath = dist;
}
}
if (Integer.MAX_VALUE == minPath) {
minPath = -1;
}
return minPath;
}
private Ancestor computeAncestor(Iterable<Integer> v, Iterable<Integer> w) {
BreadthFirstDirectedPaths bfsFromV = new BreadthFirstDirectedPaths(digraph, v);
BreadthFirstDirectedPaths bfsFromW = new BreadthFirstDirectedPaths(digraph, w);
Ancestor ancestor = new Ancestor();
ancestor.vertex = -1;
ancestor.dist = Integer.MAX_VALUE;
for (int vertex = 0; vertex < digraph.V(); vertex++) {
if (isAnAncestor(vertex, bfsFromV, bfsFromW)) {
int distToVertex = bfsFromV.distTo(vertex) + bfsFromW.distTo(vertex);
if (distToVertex < ancestor.dist) {
ancestor.vertex = vertex;
ancestor.dist = distToVertex;
}
}
}
if (ancestor.dist == Integer.MAX_VALUE) ancestor.dist = -1;
return ancestor;
}
// if retDist is set, then return shortest dist
// else return shortest ancestor
private int get_dist_ancestor(Iterable<Integer> v, Iterable<Integer> w, boolean retDist) {
int dist = INFINITY;
int synset = -1;
BreadthFirstDirectedPaths bfsA = new BreadthFirstDirectedPaths(this.graph, v);
BreadthFirstDirectedPaths bfsB = new BreadthFirstDirectedPaths(this.graph, w);
for (int i = 0; i < this.graph.V(); i++) {
if (bfsA.distTo(i) != INFINITY && bfsB.distTo(i) != INFINITY) {
int currentDist = bfsA.distTo(i) + bfsB.distTo(i);
if (currentDist < dist) {
synset = i;
dist = currentDist;
}
}
}
if (dist == INFINITY) {
return -1;
}
if (retDist) {
return dist;
} else {
return synset;
}
}
private boolean isAnAncestor(
int vertex, BreadthFirstDirectedPaths bfsFromV, BreadthFirstDirectedPaths bfsFromW) {
return bfsFromV.hasPathTo(vertex) && bfsFromW.hasPathTo(vertex);
}