1

public ArrayList<ArrayList<Integer>> combine(int n, int k) {  
   ArrayList<ArrayList<Integer>> resSet = new ArrayList<ArrayList<Integer>>();  
   if (k == 1) {  
     for (int i=1; i<=n; ++i) {  
       ArrayList<Integer> res = new ArrayList<Integer>();  
       res.add(i);  
       resSet.add(res);  
     }  
     return resSet;  
   }  
   for (int i=n; i>=k; --i) {  
     ArrayList<ArrayList<Integer>> results = combine(i-1, k-1);  
     for (ArrayList<Integer> res : results) {  
       res.add(i);  
       resSet.add(res);  
     }  
   }  
   return resSet;  
 }  

double result = 1;
		int count = 0;
		while(count != n) {
			int multi = 1; 
			double tmp = x;
			while(count < n) {
				if(count + multi > n) break;
				result *= tmp;
				count += multi;
				tmp *= tmp;
				multi *=2;
				
			}
		}