Medium 40题 Combination Sum II

Question:

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.
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]
]

Solution: 与39题很像 复杂了点，加了判断条件
public class Solution {
public List<List<Integer>> combinationSum2(int[] candidates, int target) {
Arrays.sort(candidates);
List<List<Integer>> ans=new ArrayList<List<Integer>>();
f(ans,new ArrayList<Integer>(),target,candidates,0);
return ans;
}
public void f(List<List<Integer>> ans,List<Integer> tmp, int target, int[] candidates, int start)
{
if(target==0)
{
ans.add(new ArrayList<Integer>(tmp));
return;
}
else if(target>0)
{
for(int i=start;i<=candidates.length-1&&target>=candidates[i];i++)
{
if((i!=start&&candidates[i]!=candidates[i-1])||i==start)
{
tmp.add(candidates[i]);
f(ans, tmp, target-candidates[i],candidates, i+1);
tmp.remove(tmp.size()-1);
}
}
}
}
}