[String] divided word palindrome

Note palindromic word is divided, not to determine whether a string is a palindrome big string

The general idea:

dfs went just fine.

· See a small conclusion: if required output all possible solutions, often use a depth-first search. If it is required to find the optimal solution, or the number of the solution, often using dynamic programming.

 

· There is a very powerful point: string reverse iterator rbegin () and rend () , see Figure:

So, to determine whether a string is a palindrome, just one sentence :

return s == string(s.rbegin(),s.rend());  //看s的反向是不是等于s

 

* Note: substr (the starting point, the string length of the substring )

AC Code:

class Solution {
public:
    vector<vector<string>> partition(string s) {
        vector<vector<string>> res;
        vector<string> cur;
        dfs(res,cur,s);
        return res;
    }
    
    void dfs(vector<vector<string>> &res, vector<string> &cur, string s)
    {
        if(s=="")
        {
            res.push_back(cur);
            return;
        }
        for(int i=1;i<=s.size();i++)
        {
            string sub = s.substr(0,i);
            if(isPalindrome(sub))
            {
                cur.push_back(sub);
                dfs(res,cur,s.substr(i,s.size()-i)); 
                cur.pop_back(); //pop_back是移除vector最后一个元素，也就是移除这里加入的sub
            }
        }
    }
    
    bool isPalindrome(string s)
    {
        return s == string(s.rbegin(),s.rend());
    }
    
};