import java.util.List; public class Assembler { /** * Creates a new Assembler co
ID: 3756042 • Letter: I
Question
import java.util.List;
public class Assembler {
/**
* Creates a new Assembler containing a list of fragments.
*
* The list is copied into this assembler so that the original list will not
* be modified by the actions of this assembler.
*
* @param fragments
*/
public Assembler(List<Fragment> fragments) {
}
/**
* Returns the current list of fragments this assembler contains.
*
* @return the current list of fragments
*/
public List<Fragment> getFragments() {
return null;
}
/**
* Attempts to perform a single assembly, returning true iff an assembly was
* performed.
*
* This method chooses the best assembly possible, that is, it merges the
* two fragments with the largest overlap, breaking ties between merged
* fragments by choosing the shorter merged fragment.
*
* Merges must have an overlap of at least 1.
*
* After merging two fragments into a new fragment, the new fragment is
* inserted into the list of fragments in this assembler, and the two
* original fragments are removed from the list.
*
* @return true iff an assembly was performed
*/
public boolean assembleOnce() {
return false;
}
/**
* Repeatedly assembles fragments until no more assembly can occur.
*/
public void assembleAll() {
}
}
Explanation / Answer
Assembler.java
import java.util.ArrayList;
import java.util.List;
public class Assembler {
public List<Fragment> Fragments = new ArrayList<Fragment>();
/**
* Creates a new Assembler containing a list of fragments.
*
* The list is copied into this assembler so that the original list
* will not be modified by the actions of this assembler.
*
* @param fragments
*/
public Assembler(List<Fragment> fragments) {
for(int i = 0; i<fragments.size(); i++){
Fragments.add(fragments.get(i));
}
}
/**
* Returns the current list of fragments this assembler contains.
* @return the current list of fragments
*/
public List<Fragment> getFragments() {
return Fragments;
}
/**
* Attempts to perform a single assembly, returning true if an assembly was performed.
*
* This method chooses the best assembly possible, that is,
* it merges the two fragments with the largest overlap, breaking ties
* between merged fragments by choosing the shorter merged fragment.
*
* Merges must have an overlap of at least 1.
*
* After merging two fragments into a new fragment, the new fragment is inserted into
* the list of fragments in this assembler, and the two original fragments are removed
* from the list.
*
* @return true iff an assembly was performed
*/
public boolean assembleOnce() {
int c = 0;
int maxoverlap = -1;
Fragment m1 = null, m2 = null, m = null;
for(Fragment frag1 : Fragments){
for(Fragment frag2 : Fragments){
if(frag1 == null || frag2 == null){
return false;
}
if(frag1!=frag2){
c = frag1.calculateOverlap(frag2);
if(c>maxoverlap){
maxoverlap = c;
m1 = frag1;
m2 = frag2;
}
}
}
}
if(maxoverlap>0){
Fragments.remove(m1);
Fragments.remove(m2);
m = m1.mergedWith(m2);
Fragments.add(m);
return true;
}
else {
return false;
}
}
/**
* Repeatedly assembles fragments until no more assembly can occur.
*/
public void assembleAll() {
while(assembleOnce() !=false){
assembleOnce();
}
}
}
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