剑指offer 027、字符串的排列

题目

题解

DFS + 回溯

还不会做，看的秀哥的做法。会了继续补充

class Solution {
public:
    vector<string> result;
    
    void permutationAdjust(string &s,int begin,int end) {
        if(begin == end){
            result.push_back(s);
            return ;
        }
        unordered_map<int,int> visited;
        for(int i = begin; i<= end; ++i){
            if(visited[s[i]] == 1) continue;
            swap(s[i],s[begin]);
            permutationAdjust(s,begin+1,end);
            swap(s[i],s[begin]);
            visited[s[i]] =1;
        }
    }
    vector<string> Permutation(string str) {
        if (str.size() == 0) return vector<string>();
        
        permutationAdjust(str,0,str.size()-1);
        sort(result.begin(), result.end());
        return result;
    }
};