LeetCode(Permutations)

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Permutations
深搜：

class Solution {public:    vector<vector<int> > permute(vector<int>& num) {        sort(num.begin(),num.end());        vector<vector<int> > result;        vector<int> path;        dfs(num,result,path);        return result;    }    void dfs(vector<int> &num,vector<vector<int> > &result,vector<int> &path)    {        if(path.size()==num.size())        {            result.push_back(path);            return;        }        for(int i=0;i<num.size();++i)        {            if(find(path.begin(),path.end(),num[i])==path.end())            {                path.push_back(num[i]);                dfs(num,result,path);                path.pop_back();            }        }    }};

Permutations II
深搜：

class Solution {public:    vector<vector<int> > permuteUnique(vector<int>& num) {        sort(num.begin(),num.end());        vector<vector<int>> result;        vector<int> path;         unordered_map<int,int> map;        for(int i=0;i<num.size();++i)        {            if(map.find(num[i])==map.end())map[num[i]]=1;            else ++map[num[i]];        }        dfs(num,result,path,map);        return result;    }    void dfs(vector<int> &num,vector<vector<int> > &result,vector<int> &path,unordered_map<int,int> &map)     {        if(path.size()==num.size())result.push_back(path);        for(unordered_map<int,int>::iterator i=map.begin();i!=map.end();++i)         {            int cnt=0;            for(int j=0;j<path.size();++j)             {                if(path[j]==i->first)++cnt;            }            if(cnt<i->second)            {                path.push_back(i->first);                dfs(num,result,path,map);                path.pop_back();            }        }    }};

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