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Two2DIterator
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Two2DIterator
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import java.util.Iterator;
import java.util.*;
public class Two2DIterator implements Iterator<Integer> {
private Iterator<List<Integer>> rowIter;
private Iterator<Integer> colIter;
public Two2DIterator(List<List<Integer>> vec2d) {
rowIter = vec2d.iterator();
colIter = Collections.emptyIterator();
}
@Override
public boolean hasNext() {
// TODO Auto-generated method stub
while((colIter==null|| !colIter.hasNext())&&rowIter.hasNext()){
colIter = rowIter.next().iterator();
}
return colIter!=null&&colIter.hasNext();
}
@Override
public Integer next() {
// TODO Auto-generated method stub
return colIter.next();
}
public void remove() {
while((colIter==null&&rowIter.hasNext())) {
colIter=rowIter.next().iterator();
}
if(colIter!=null) {
colIter.remove();
}
}
}
==============================
public class TwoDIterator {
private List<List<Integer>> array;
private int rowId;
private int colId;
public TwoDIterator(List<List<Integer>> array){
this.array=array;
this.rowId=0;
this.colId=0;
}
public boolean hasNext(){
if(array==null||array.size()==0) return false;
while(rowId<array.size()&&(array.get(rowId)==null||array.get(rowId).isEmpty())){
rowId++;
}
return rowId<array.size();
}
public int getNext(){
int result = array.get(rowId).get(colId);
colId++;
//if last item in current row, move to next row
if(colId== array.get(rowId).size()){
rowId++;
colId=0;
}
return result;
}
public void remove(){
List<Integer> listToRemove = new ArrayList<>();
int rowToRemove;
int colToRemove;
//1. if item is last in row
if(colId==0){
rowToRemove = rowId-1;
listToRemove = array.get(rowToRemove);
colToRemove = listToRemove.size()-1;
listToRemove.remove(colToRemove);
}
else{
rowToRemove = rowId;
listToRemove = array.get(rowToRemove);
colToRemove = colId-1;
listToRemove.remove(colToRemove);
}
if(listToRemove.isEmpty()){
array.remove(listToRemove);
rowId--;
}
if(colId!=0){
colId--;
}
}
public static void main(String[] args) {
List<List<Integer>> array = new ArrayList<>();
List<Integer> row1 = new ArrayList<>();
row1.add(1);
row1.add(2);
row1.add(3);
array.add(row1);
List<Integer> row3 = new ArrayList<>();
array.add(row3);
List<Integer> row2 = new ArrayList<>();
row2.add(4);
row2.add(5);
array.add(row2);
TwoDIterator sol = new TwoDIterator(array);
while (sol.hasNext()) {
int result = sol.getNext();
System.out.println(result);
if (result == 3) {
sol.remove();
}
}
System.out.println();
for (List<Integer> row : array) {
for (Integer elem : row) {
System.out.println(elem);
}
}
}
}