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Wordnode.java
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Wordnode.java
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import java.util.ArrayList;
import java.util.LinkedList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.List;
public class Wordnode{
public String word;
public List<Wordnode> neighbors;
public Wordnode(String word){
this.word = word;
this.neighbors = new ArrayList<Wordnode>();
}
public Wordnode(){
this("");
}
public String toString(){
return this.word;
}
// separate implementation to avoid repeatedly checking
// empty HashSet
public List<String> shortestPath(Wordnode dest, int limit){
return shortestPath(dest, limit, new HashSet<Wordnode>());
}
public List<String> shortestPath(Wordnode dest, int limit, Set<Wordnode> avoids){
Set<Wordnode> visited = avoids;
Map<Wordnode, Wordnode> previous = new HashMap<>();
LinkedList<Wordnode> q = new LinkedList<Wordnode>();
previous.put(this, null);
if(!avoids.contains(this))
q.add(this);
Wordnode curr = null;
boolean found = false;
while(!q.isEmpty()){
curr = q.removeLast();
visited.add(curr);
if(curr == dest)
{
found = true;
break;
}
else{
for(Wordnode n: curr.neighbors){
if(!visited.contains(n)){
q.addFirst(n);
if(!previous.containsKey(n))
previous.put(n, curr);
}
}
}
}
if(!found)
return null;
return traceBack(curr, previous);
}
public List<String> traceBack(Wordnode curr, Map<Wordnode, Wordnode> previous){
LinkedList<String> ret = new LinkedList<>();
while(curr != null){
ret.addFirst(curr.word);
curr = previous.get(curr);
}
return ret;
}
}