栈:
package practice0730;
import java.util.ArrayList;
public class Mstack {
ArrayList<Integer> arr=new ArrayList<Integer>();
int top=-1;
public void push(Integer integer){
arr.add(top, integer);
top++;
}
public Integer pop() {
top--;
int r=0;
try {
r=arr.get(top );
arr.remove(top);
} catch (Exception e) {
System.out.println("栈已为空");
return -1;
}
return r;
}
public boolean isEmpty() {
if(top<=0){
return true;
}else{
return false;
}
}
}
队列:
package practice0730; import java.util.ArrayList; public class quee { ArrayList<Integer> arr=new ArrayList<Integer>(); int top=0; int bottom=0; public void push(Integer integer){ arr.add(top, integer); top++; } public Integer pop() { int r=0; try { r=arr.get(0 ); arr.remove(0); top--; } catch (Exception e) { System.out.println("队列已为空"); return -1; } return r; } public boolean isEmpty() { if(top<=0){ return true; }else{ return false; } } }