Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.
Each number in C may only be used once in the combination.
Note:
- All numbers (including target) will be positive integers.
- Elements in a combination (a1, a2, … , ak) must be in non-descending order. (ie, a1 ≤ a2 ≤ … ≤ ak).
- The solution set must not contain duplicate combinations.
For example, given candidate set 10,1,2,7,6,1,5 and target 8,
A solution set is: [1, 7] [1, 2, 5] [2, 6] [1, 1, 6]
public class Solution {
public IList<IList<int>> CombinationSum2(int[] candidates, int target) {
List<IList<int>> result = new List<IList<int>>();
List<int> res=new List<int>();
Array.Sort(candidates);
calulate(candidates,,target,res,result);
return result;
}
void calulate(int[] candidates, int cur,int target,List<int> res,List<IList<int>> result)
{
)
{
result.Add(new List<int>(res));
return;
}
)
{
return;
}
for(int i=cur;i<candidates.Length;i++)
{
])
continue;
res.Insert(res.Count,candidates[i]);
calulate(candidates,i+,target-candidates[i],res,result);
res.RemoveAt(res.Count-);
}
}
}
1 这个算法可以非常高效的计算出结果。
2 这个算法是在方法中调用方法本身。