/*
* Should return path from initial node to terminal;
* Means getting new path-backtracker
*/
public Counter bfs(int initNode, int terminalNode) {
Counter shortestPaths = new Counter();
Counter currentNodes = new Counter();
Counter newNodes = new Counter();
shortestPaths.add(initNode, 0);
newNodes.add(initNode, 0);
while (!newNodes.isEmpty()) {
currentNodes = new Counter(newNodes);
newNodes = new Counter();
for (int r : currentNodes.keySet()) {
Counter row = this.getRow(r);
for (int c : row.keySet()) {
// Weighted case: later paths can be shorter than first path
double pathLength = currentNodes.get(r) + row.get(c);
if (pathLength < shortestPaths.getPath(c)) {
newNodes.put(c, pathLength);
shortestPaths.put(c, pathLength);
}
}
}
if (shortestPaths.getPath(terminalNode) < Double.MAX_VALUE / 2.0) {
break;
}
}
return shortestPaths;
}
public Counter getCol(int c) {
Counter col = new Counter();
for (int r : rows) {
if (this.getRow(r).containsKey(c)) {
col.put(r, this.get(r, c));
}
}
return col;
}
public void set(int r, int c, double v) {
Counter row = this.getRow(r);
if (row.isEmpty()) {
mat.put(r, row);
}
row.put(c, v);
rows.add(r);
cols.add(c);
}
