Need help improve the code

Question

I have this file but I need to improve the code on some method. The methods are addNode, deleteNode, saveNode, findLader and are they anyway for me to iliminate the findsmallest method?
here is the code
import java.io.*;
import java.util.LinkedList;
import java.util.Stack;
import javax.swing.*;
public class Graph {
private LinkedList graph;
private BufferedReader inputFile;
public Graph() {
graph = new LinkedList();
// read the words from the given file
// create a GraphNode
// Add the node to the graph
public void createGraph(String fileName) throws IOException {
inputFile = new BufferedReader(
new InputStreamReader(new FileInputStream("word.txt")));
// Convert the linkedlist to an array 'a'
// sort the array 'a'
// create a string from all elements in 'a'
// return the string
public String printGraph() {
String output = new String();
// will contain String objects
// ... do some work with the list, adding, removing String objects
String[] a = new String[graph.size()];
graph.toArray(a);
// now stringArray contains all the element from linkedList
quickSort(a, 0, a.size() - 1);
for(int i=0;i<a.length;++i)
output = output + new String(a.toString())+"\n";
return output;
private static void quickSort(Comparable[] theArray,
int first, int last) {
// Sorts the items in an array into ascending order.
// Precondition: theArray[first..last] is an array.
// Postcondition: theArray[first..last] is sorted.
// Calls: partition.
int pivotIndex;
if (first < last) {
// create the partition: S1, Pivot, S2
pivotIndex = partition(theArray, first, last);
// sort regions S1 and S2
quickSort(theArray, first, pivotIndex-1);
quickSort(theArray, pivotIndex+1, last);
} // end if
} // end quickSort
private static int partition(Comparable[] theArray,
int first, int last) {
// Partitions an array for quicksort.
// Precondition: theArray[first..last] is an array;
// first <= last.
// Postcondition: Returns the index of the pivot element of
// theArray[first..last]. Upon completion of the method,
// this will be the index value lastS1 such that
// S1 = theArray[first..lastS1-1] < pivot
// theArray[lastS1] == pivot
// S2 = theArray[lastS1+1..last] >= pivot
// Calls: choosePivot.
// tempItem is used to swap elements in the array
Comparable tempItem;
// place pivot in theArray[first]
//choosePivot(theArray, first, last);
Comparable pivot = theArray[first]; // reference pivot
// initially, everything but pivot is in unknown
int lastS1 = first; // index of last item in S1
// move one item at a time until unknown region is empty
for (int firstUnknown = first + 1; firstUnknown <= last;
++firstUnknown) {
// Invariant: theArray[first+1..lastS1] < pivot
// theArray[lastS1+1..firstUnknown-1] >= pivot
// move item from unknown to proper region
if (theArray[firstUnknown].compareTo(pivot) < 0) {
// item from unknown belongs in S1
++lastS1;
tempItem = theArray[firstUnknown];
theArray[firstUnknown] = theArray[lastS1];
theArray[lastS1] = tempItem;
} // end if
// else item from unknown belongs in S2
} // end for
// place pivot in proper position and mark its location
tempItem = theArray[first];
theArray[first] = theArray[lastS1];
theArray[lastS1] = tempItem;
return lastS1;
} // end partition
// Given a new word, add it to the graph
public void addNode(String word) {
GraphNode node = new GraphNode(word);
if(graph.contains(node)){
JOptionPane.showMessageDialog(null,"Duplicate Word, operation terminated");
for(int i=0; i<graph.size(); ++i) {
if(isAnEdge((String)(((GraphNode)graph.get(i)).getVertex()),(String)(node.getVertex()))) {
EdgeNode e1 = new EdgeNode((String)node.getVertex(),1);
EdgeNode e2 = new EdgeNode((String)((GraphNode)graph.get(i)).getVertex(),1);
node.addEdge(e2);
((GraphNode)graph.get(i)).addEdge(e1);
graph.add(node);
public boolean deleteNode(String word) {
GraphNode node = new GraphNode(word);
EdgeNode n = new EdgeNode(word,1);
if(!graph.contains(node)) {
return false;
else {
for(int i=0; i<graph.size();++i) {
((GraphNode)graph.get(i)).getEdgeList().remove(n);
graph.remove(node);
return true;
public void save(String fileName) {
try {
PrintWriter output = new PrintWriter(new FileWriter("word.txt"));
for(int i=0; i< graph.size();++i) {
output.println(((GraphNode)graph.get(i)).getVertex());
output.close();
catch (IOException e) {
// given two word, find the ladder (using dijkstra's algorithm
// create a string for the ladder and return it
public String findLadder(String start,String end) {
String ladder = new String();
GraphNode sv = new GraphNode(start);
GraphNode ev = new GraphNode(end);
if(!graph.contains(sv)) {
JOptionPane.showMessageDialog(null,start + " not in graph");
return null;
if(!graph.contains(ev)) {
JOptionPane.showMessageDialog(null,end + " not in graph");
return null;
LinkedList distance = new LinkedList(((GraphNode)graph.get(graph.indexOf(sv))).getEdgeList());
LinkedList visited = new LinkedList();
visited.add(start);
LinkedList path = new LinkedList();
path.add(new PathNode(start,"****"));
for(int i=0; i<distance.size();++i) {
PathNode p = new PathNode((String)((EdgeNode)distance.get(i)).getKey(),start);
path.add(p);
while(!visited.contains(end)) {
EdgeNode min = findSmallest(distance,visited);
String v = (String)min.getVertex();
if(v.equals("****"))
return null;
visited.add(v);
// for(int i=0;i<graph.size();++i) {
// String u = (String)(((GraphNode)(graph.get(i))).getVertex());
GraphNode temp1 = new GraphNode(v);
int index = graph.indexOf(temp1);
LinkedList l = new LinkedList(((GraphNode)graph.get(index)).getEdgeList());
for(int i=0;i<l.size();++i)
String u = (String)(((EdgeNode)(l.get(i))).getVertex());
if(!visited.contains(u)) {
int du=999, dv=999, avu=999;
dv = min.getCost();
EdgeNode edge = new EdgeNode(u,1);
if(distance.contains(edge)) {
du = ((EdgeNode)(distance.get(distance.indexOf(edge)))).getCost();
GraphNode temp = new GraphNode(v);
GraphNode node = ((GraphNode)(graph.get(graph.indexOf(temp))));
LinkedList edges = node.getEdgeList();
if(edges.contains(edge)) {
avu = ((EdgeNode)(edges.get(edges.indexOf(new EdgeNode(u,1))))).getCost();
if( du > dv+avu) {
if(du == 999) {
distance.add(new EdgeNode(u,dv+avu));
path.add(new PathNode(u,v));
else {
((EdgeNode)(distance.get(distance.indexOf(u)))).setCost(dv+avu);
((PathNode)(path.get(path.indexOf(u)))).setEnd(v);
if(!path.contains(new PathNode(end,"")))
return null;
LinkedList pathList = new LinkedList();
for(int i=0;i<path.size();++i) {
PathNode n = (PathNode)path.get(path.indexOf(new PathNode(end,"****")));
if(n.getEnd().compareTo("****") != 0) {
pathList.addFirst(end);
n = (PathNode)path.get(path.indexOf(new PathNode(n.getEnd(),"****")));
end = n.getStart();
pathList.addFirst(start);
for(int i=0;i<pathList.size()-1;++i) {
ladder = ladder + ((String)(pathList.get(i))) + " --> ";
ladder = ladder + ((String)(pathList.get(pathList.size()-1)));
return ladder;
private EdgeNode findSmallest(LinkedList distance, LinkedList visited) {
EdgeNode min = new EdgeNode("****",999);
for(int i=0;i<distance.size();++i) {
String node = (String)(((EdgeNode)distance.get(i)).getVertex());
if(!visited.contains(node)) {
if(((EdgeNode)distance.get(i)).getCost()<min.getCost()) {
min = (EdgeNode)distance.get(i);
return min;
// class that represents nodes inserted into path set
private class PathNode {
protected String sv;
protected String ev;
public PathNode(String s,String e) {
sv = s;
ev = e;
public String getEnd() {
return ev;
public String getStart() {
return sv;
public void setEnd(String n) {
ev = n;
public boolean equals(Object o) {
return this.sv.equals(((PathNode)o).sv);
public String toString() {
return "("+sv+":"+ev+")";
thank you

Answer 1

let me fix my misstake which was point out by some one in here and thank you ofr do so because I'm new at this.
I have this file but I need to improve the code on some method. The methods are addNode, deleteNode, saveNode, findLader and are they anyway for me to iliminate the findsmallest method?
here is the code
import java.io.*;
import java.util.LinkedList;
import java.util.Stack;
import javax.swing.*;
public class Graph {
private LinkedList graph;
private BufferedReader inputFile;
public Graph() {
graph = new LinkedList();
// read the words from the given file
// create a GraphNode
// Add the node to the graph
public void createGraph(String fileName) throws IOException {
inputFile = new BufferedReader(
new InputStreamReader(new FileInputStream("word.txt")));
// Convert the linkedlist to an array 'a'
// sort the array 'a'
// create a string from all elements in 'a'
// return the string
public String printGraph() {
String output = new String();
// will contain String objects
// ... do some work with the list, adding, removing String objects
String[] a = new String[graph.size()];
graph.toArray(a);
// now stringArray contains all the element from linkedList
quickSort(a, 0, a.size() - 1);
for(int i=0;i<a.length;++i)
output = output + new String(a.toString())+"\n";
return output;
private static void quickSort(Comparable[] theArray,
int first, int last) {
// Sorts the items in an array into ascending order.
// Precondition: theArray[first..last] is an array.
// Postcondition: theArray[first..last] is sorted.
// Calls: partition.
int pivotIndex;
if (first < last) {
// create the partition: S1, Pivot, S2
pivotIndex = partition(theArray, first, last);
// sort regions S1 and S2
quickSort(theArray, first, pivotIndex-1);
quickSort(theArray, pivotIndex+1, last);
} // end if
} // end quickSort
private static int partition(Comparable[] theArray,
int first, int last) {
// Partitions an array for quicksort.
// Precondition: theArray[first..last] is an array;
// first <= last.
// Postcondition: Returns the index of the pivot element of
// theArray[first..last]. Upon completion of the method,
// this will be the index value lastS1 such that
// S1 = theArray[first..lastS1-1] < pivot
// theArray[lastS1] == pivot
// S2 = theArray[lastS1+1..last] >= pivot
// Calls: choosePivot.
// tempItem is used to swap elements in the array
Comparable tempItem;
// place pivot in theArray[first]
//choosePivot(theArray, first, last);
Comparable pivot = theArray[first]; // reference pivot
// initially, everything but pivot is in unknown
int lastS1 = first; // index of last item in S1
// move one item at a time until unknown region is empty
for (int firstUnknown = first + 1; firstUnknown <= last;
++firstUnknown) {
// Invariant: theArray[first+1..lastS1] < pivot
// theArray[lastS1+1..firstUnknown-1] >= pivot
// move item from unknown to proper region
if (theArray[firstUnknown].compareTo(pivot) < 0) {
// item from unknown belongs in S1
++lastS1;
tempItem = theArray[firstUnknown];
theArray[firstUnknown] = theArray[lastS1];
theArray[lastS1] = tempItem;
} // end if
// else item from unknown belongs in S2
} // end for
// place pivot in proper position and mark its location
tempItem = theArray[first];
theArray[first] = theArray[lastS1];
theArray[lastS1] = tempItem;
return lastS1;
} // end partition
// Given a new word, add it to the graph
public void addNode(String word) {
GraphNode node = new GraphNode(word);
if(graph.contains(node)){
JOptionPane.showMessageDialog(null,"Duplicate Word, operation terminated");
for(int i=0; i<graph.size(); ++i) {
if(isAnEdge((String)(((GraphNode)graph.get(i)).getVertex()),(String)(node.getVertex()))) {
EdgeNode e1 = new EdgeNode((String)node.getVertex(),1);
EdgeNode e2 = new EdgeNode((String)((GraphNode)graph.get(i)).getVertex(),1);
node.addEdge(e2);
((GraphNode)graph.get(i)).addEdge(e1);
graph.add(node);
public boolean deleteNode(String word) {
GraphNode node = new GraphNode(word);
EdgeNode n = new EdgeNode(word,1);
if(!graph.contains(node)) {
return false;
else {
for(int i=0; i<graph.size();++i) {
((GraphNode)graph.get(i)).getEdgeList().remove(n);
graph.remove(node);
return true;
public void save(String fileName) {
try {
PrintWriter output = new PrintWriter(new FileWriter("word.txt"));
for(int i=0; i< graph.size();++i) {
output.println(((GraphNode)graph.get(i)).getVertex());
output.close();
catch (IOException e) {
// given two word, find the ladder (using dijkstra's algorithm
// create a string for the ladder and return it
public String findLadder(String start,String end) {
String ladder = new String();
GraphNode sv = new GraphNode(start);
GraphNode ev = new GraphNode(end);
if(!graph.contains(sv)) {
JOptionPane.showMessageDialog(null,start + " not in graph");
return null;
if(!graph.contains(ev)) {
JOptionPane.showMessageDialog(null,end + " not in graph");
return null;
LinkedList distance = new LinkedList(((GraphNode)graph.get(graph.indexOf(sv))).getEdgeList());
LinkedList visited = new LinkedList();
visited.add(start);
LinkedList path = new LinkedList();
path.add(new PathNode(start,"****"));
for(int i=0; i<distance.size();++i) {
PathNode p = new PathNode((String)((EdgeNode)distance.get(i)).getKey(),start);
path.add(p);
while(!visited.contains(end)) {
EdgeNode min = findSmallest(distance,visited);
String v = (String)min.getVertex();
if(v.equals("****"))
return null;
visited.add(v);
// for(int i=0;i<graph.size();++i) {
// String u = (String)(((GraphNode)(graph.get(i))).getVertex());
GraphNode temp1 = new GraphNode(v);
int index = graph.indexOf(temp1);
LinkedList l = new LinkedList(((GraphNode)graph.get(index)).getEdgeList());
for(int i=0;i<l.size();++i)
String u = (String)(((EdgeNode)(l.get(i))).getVertex());
if(!visited.contains(u)) {
int du=999, dv=999, avu=999;
dv = min.getCost();
EdgeNode edge = new EdgeNode(u,1);
if(distance.contains(edge)) {
du = ((EdgeNode)(distance.get(distance.indexOf(edge)))).getCost();
GraphNode temp = new GraphNode(v);
GraphNode node = ((GraphNode)(graph.get(graph.indexOf(temp))));
LinkedList edges = node.getEdgeList();
if(edges.contains(edge)) {
avu = ((EdgeNode)(edges.get(edges.indexOf(new EdgeNode(u,1))))).getCost();
if( du > dv+avu) {
if(du == 999) {
distance.add(new EdgeNode(u,dv+avu));
path.add(new PathNode(u,v));
else {
((EdgeNode)(distance.get(distance.indexOf(u)))).setCost(dv+avu);
((PathNode)(path.get(path.indexOf(u)))).setEnd(v);
if(!path.contains(new PathNode(end,"")))
return null;
LinkedList pathList = new LinkedList();
for(int i=0;i<path.size();++i) {
PathNode n = (PathNode)path.get(path.indexOf(new PathNode(end,"****")));
if(n.getEnd().compareTo("****") != 0) {
pathList.addFirst(end);
n = (PathNode)path.get(path.indexOf(new PathNode(n.getEnd(),"****")));
end = n.getStart();
pathList.addFirst(start);
for(int i=0;i<pathList.size()-1;++i) {
ladder = ladder + ((String)(pathList.get(i))) + " --> ";
ladder = ladder + ((String)(pathList.get(pathList.size()-1)));
return ladder;
private EdgeNode findSmallest(LinkedList distance, LinkedList visited) {
EdgeNode min = new EdgeNode("****",999);
for(int i=0;i<distance.size();++i) {
String node = (String)(((EdgeNode)distance.get(i)).getVertex());
if(!visited.contains(node)) {
if(((EdgeNode)distance.get(i)).getCost()<min.getCost()) {
min = (EdgeNode)distance.get(i);
return min;
// class that represents nodes inserted into path set
private class PathNode {
protected String sv;
protected String ev;
public PathNode(String s,String e) {
sv = s;
ev = e;
public String getEnd() {
return ev;
public String getStart() {
return sv;
public void setEnd(String n) {
ev = n;
public boolean equals(Object o) {
return this.sv.equals(((PathNode)o).sv);
public String toString() {
return "("+sv+":"+ev+")";
}thank you