【leetcode】78. Subsets

小do在努力

于 2015-10-08 20:29:42 发布

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分类专栏：【leetcode】文章标签： leetcode subsets dfs

本文链接：https://blog.youkuaiyun.com/zone_programming/article/details/48978325

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直接dfs，注意采用vector的erase和remove

/**
 *  @author         johnsondu
 *  @time           20:27 8th Oct 2015
 *  @type           dfs
 *  @url            https://leetcode.com/problems/subsets/
 *  @status         Accepted
 */

class Solution {
public:
    void dfs(int idx, vector<int> &tmp, vector<vector<int>> &ans, vector<int>& nums)
    {
        sort(tmp.begin(), tmp.end());
        ans.push_back(tmp);
        for(int j = idx; j < nums.size(); j ++) {
            tmp.push_back(nums[j]);
            dfs(j + 1, tmp, ans, nums);
            tmp.erase(remove(tmp.begin(),tmp.end(),nums[j]),tmp.end());
        }
    }

    vector<vector<int>> subsets(vector<int>& nums) {
        vector<vector<int>> ans;
        vector<int> tmp;
        ans.push_back(tmp);
        if(nums.size() == 0) return ans;
        
        for(int i = 0; i < nums.size(); i ++) {
            tmp.push_back(nums[i]);
            dfs(i + 1, tmp, ans, nums);
            tmp.erase(remove(tmp.begin(),tmp.end(),nums[i]),tmp.end());
        }

        return ans;
    }
};