首页 > 代码库 > Combinations

Combinations

Given two integers n and k, return all possible combinations of k numbers out of 1 ... n.

For example,
If n = 4 and k = 2, a solution is:

[  [2,4],  [3,4],  [2,3],  [1,2],  [1,3],  [1,4],]
这道题完全是凭着感觉A出来的
 1 public class Solution { 2     private List<List<Integer>> result = new ArrayList<List<Integer>>(); 3      4     public List<List<Integer>> combine(int n, int k) { 5         List<Integer> cur = new ArrayList<Integer>(); 6          7         getResult(cur, 1, 0, k, n); 8         9         return result;10     }11     public void getResult(List<Integer> cur, int start, int dep, int depMax, int end){12         if(dep == depMax){13             List<Integer> temp = new ArrayList<Integer>(cur);14             result.add(temp);15         }else{16             for(int i = start; i <= end; i++){17                 cur.add(i);18                 getResult(cur, i + 1, dep + 1, depMax, end);19                 cur.remove(cur.size() - 1);20             }21         }22     }23 }

 

Combinations