leetcode：word-break-ii

1.题目描述

Given a string s and a dictionary of words dict, add spaces in s to construct a sentence where each word is a valid dictionary word.

Return all such possible sentences.

For example, given
s ="catsanddog",
dict =["cat", "cats", "and", "sand", "dog"].

A solution is["cats and dog", "cat sand dog"].

2.题目分析

3.代码实现

class Solution {public:    vector<bool>* dp;    vector<string> mystring;    vector<string> result;    vector<string> wordBreak(string s, unordered_set<string> &dict) {        dp = new vector<bool>[s.size()];        for(int i =0;i<s.size();i++)        {            for(int j =i;j<s.size();j++)            {                dp[i].push_back(isMatch(s.substr(i,j-i+1),dict));//dp[i][j]表示i到i+j字符串在字典中            }        }                output(s.size()-1, s);        return result;    }        void output(int i, string s)//比较复杂    {        if(i==-1)说明可以实现一种情况的分割，就可以进行输出了        {            string str;            for(int i=mystring.size()-1;i>=0;i--)            {                str += mystring[i];                if(i!=0)                {                    str.push_back(' ');                }            }            result.push_back(str);        }        else        {            for(int k=0;k<=i;k++)            {                if(dp[k][i-k])                {                    mystring.push_back(s.substr(k,i-k+1));                    output(k-1,s);                    mystring.pop_back();                }            }        }    }    bool isMatch(string str, unordered_set<string> &dict)    {        unordered_set<string>::const_iterator got = dict.find (str);        if(got != dict.end())        {            return true;        }        else        {            return false;        }    }};