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Heap.java
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Heap.java
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import java.lang.Integer;
import java.util.ArrayList;
class Heap{
private ArrayList<Integer> eles = new ArrayList<Integer>();
public Heap(){
}
public Heap(int[] array){
for (int i = 0; i<array.length; i++){
add(array[i]);
}
}
public void add(int a){
eles.add(a);
int idx = eles.size()-1;
int par = (idx-1)/2;
while(idx != 0 && eles.get(idx)<eles.get(par)){
int tmp = eles.get(idx);
eles.set(idx,eles.get(par));
eles.set(par,tmp);
idx = par;
par = (idx-1)/2;
}
}
public int remove(){
int result = eles.remove(0);
eles.add(0,eles.remove(eles.size() - 1));
int idx = 0;
while (true){
int left = 2*idx+1;
int right = 2*idx+2;
if (right<eles.size()){
if (eles.get(idx)>eles.get(left) || eles.get(idx)>eles.get(right)){
if (eles.get(left)<eles.get(right)){
swap(idx,left);
idx = left;
}else {
swap(idx, right);
idx = right;
}
}else {
break;
}
}else if (left<eles.size()){
if (eles.get(idx)>eles.get(left)){
swap(idx,left);
idx = left;
}else {
break;
}
}else {
break;
}
}
return result;
}
private void swap(int i, int j){
int tmp = eles.get(i);
eles.set(i,eles.get(j));
eles.set(j,tmp);
}
}