Word Break

Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words.

For example, given
s = "leetcode",
dict = ["leet", "code"].

Return true because "leetcode" can be segmented as "leet code".

dp 已用，感觉良好，注意词的边界。

dp这个东西么，如果不主动去想，是想不出来的……

class Solution {
public:
    bool wordBreak(string s, unordered_set<string> &dict) {
        int n =s.size();
        vector<bool> bo(n,0);
        if(dict.find(s.substr(0,1))!=dict.end())bo[0]=1;
        //bo[0] = 1;
        for(int i = 1 ; i <= s.size() ; i++)
        {
            if(dict.find(s.substr(0,i)) != dict.end())
            {
                bo[i-1] = 1;
            }
        }
        for(int i = 1 ; i < s.size() ; i++)
        {
            if(bo[i] == 1)continue;
            for(int j = i ; j >= 0 ; j--)
            {
                
                if(bo[j] == 1 && dict.find(s.substr(j+1,i-j))!= dict.end())
                {
                    bo[i] =1;
                    break;
                }
                if(bo[n-1] == 1)return 1;
            }
        }
        if(bo[n-1] == 1)return 1;
        return 0;
    }
};