[LeetCode] word break

题目描述：

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".

解题思路：

参考链接：http://blog.csdn.net/linhuanmars/article/details/22358863

class Solution {
public:
    bool wordBreak(string s, unordered_set<string>& wordDict) {
        if (s.size() == 0) {
            return true;
        }
        
        vector<bool> result(s.size() + 1, false);
        result[0] = true;
        for (int i = 0; i < s.size(); ++i) {
            string tmp = s.substr(0, i + 1);
            for (int j = 0; j <= i; ++j) {
                if (result[j] && wordDict.find(tmp) != wordDict.end()) {
                    result[i + 1] = true;
                    break;
                }
                tmp.erase(0, 1);
            }
        }
        
        return result[s.size()];
    }
};