title
Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sums to target.
Each number in candidates 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.
Example 1:
Input: candidates = [10,1,2,7,6,1,5], target = 8,
A solution set is: [ [1, 7], [1, 2, 5], [2, 6], [1, 1, 6] ]
Example 2:
Input: candidates = [2,5,2,1,2], target = 5,
A solution set is:
[
[1,2,2],
[5]
]
solution
class Solution {
public:
void backtracking(vector<vector<int>> &res, vector<int>& t,vector<int>& can,vector<bool> &visit, int target, int start) {
if (target == 0) {
res.push_back(t);
return;
}
if (target < 0 || start == can.size())
return;
for (int i = start; i < can.size(); i++) {
if (i != 0 && can[i] == can[i - 1] && !visit[i - 1]) {
continue;
}
visit[i] = true;
t.push_back(can[i]);
backtracking(res, t, can, visit, target - can[i], i + 1);
t.pop_back();
visit[i] = false;
}
}
vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
vector<vector<int>> res;
if (candidates.size() == 0) return res;
vector<bool> visit(candidates.size());
vector<int> t;
sort(candidates.begin(), candidates.end());
backtracking(res, t, candidates, visit, target, 0);
return res;
}
};