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CombinationSumII.cpp
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47 lines (44 loc) · 1.46 KB
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/**
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]
*/
class Solution {
public:
void combinationSumUtil(vector<vector<int> >&ret, vector<int> sol,
vector<int>& num, int target, int sum, int pos) {
if (sum > target) return ;
if (sum == target) {
ret.push_back(sol);
return ;
}
for (int i = pos; i < num.size(); ++i) {
sum += num[i];
sol.push_back(num[i]);
combinationSumUtil(ret, sol, num, target, sum, i+1);
sum -= num[i];
sol.pop_back();
while (i +1 < num.size() && num[i] == num[i+1]) i++;
}
}
vector<vector<int> > combinationSum2(vector<int> &num, int target) {
vector<vector<int> > ret;
if (num.empty()) return ret;
vector<int> combination;
int sum = 0;
std::sort(num.begin(), num.end());
combinationSumUtil(ret, combination, num, target, sum, 0);
return ret;
}
};