现在的位置: 首页 > 综合 > 正文

Leetcode Combination Sum

2019年03月10日 ⁄ 综合 ⁄ 共 905字 ⁄ 字号 评论关闭

题目:

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

The same repeated number may be chosen from C unlimited number of times.

Note:

  • All numbers (including target) will be positive integers.
  • Elements in a combination (a1a2,
    … , ak) must be in non-descending order. (ie, a1 ≤ a2 ≤
    … ≤ ak).
  • The solution set must not contain duplicate combinations.

For example, given candidate set 2,3,6,7 and target 7

A solution set is: 
[7] 
[2, 2, 3] 

解题:

暴力dfs就可以


代码:

class Solution {
public:
    vector<vetor<int> > combinationSum(vector<int> &candidates, int target) {
        ans.clear();
        single.clear();
        sort(candidates.begin(), candidates.end());
        in = candidates;
        dfs(0, target);
        return ans;
    }
private:
    vector<vector<int> > ans;
    vector<int> single, in;

    void dfs(int pos, int target) {
        if(target == 0) {
            ans.push_back(single);
            return ;
        }
        for(int i = pos; i < in.size(); i ++) {
            if(in[i] > target) break;
            single.push_back(in[i]);
            dfs(i, target - in[i]);
            single.pop_back();
        }
        return;
    }
};

抱歉!评论已关闭.