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], ]
Code:
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class
Solution {public: void
findCombination(int
&n, int
&k, int
level, vector<int> &buf, vector<vector<int>> &res){ if(buf.size()==k){ res.push_back(buf); return; } for(int
i=level;i<=n;i++){ buf.push_back(i); findCombination(n,k,i+1,buf,res); buf.pop_back(); } } vector<vector<int> > combine(int
n, int
k) { vector<vector<int>> res; vector<int> buf; findCombination(n,k,1,buf,res); return
res; }}; |
原文：http://www.cnblogs.com/winscoder/p/3535434.html