[leetcode] Combination Sum II

From : https://leetcode.com/problems/combination-sum-ii/

Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums toT.

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] 

class Solution {public:    vector<vector<int> > combinationSum2(vector<int>& candidates, int target) {        vector<vector<int> > ans;        if(candidates.size()==0 || target <=0 ) return ans;        sort(candidates.begin(), candidates.end());        vector<int> cur;        find(candidates, cur, ans, 0, target);        return ans;    }    void find(vector<int>& cands, vector<int>& cur, vector<vector<int> >& ans, int index, int need) {if(need == 0) {ans.push_back(cur); return;}        int size = cands.size();        if(index >= size) return;        for(int i=index; i<size; i++) {            while(i>index && i<size && cands[i]==cands[i-1]) i++;if(i == size) break;            if(need >= cands[i]) {cur.push_back(cands[i]);                find(cands, cur, ans, i+1, need-cands[i]);cur.pop_back();            } else {                break;            }        }    }};