Solution.cpp

class Solution {
public:
    bool wordBreak(string s, vector<string>& wordDict) {
        unordered_set<string> words(wordDict.begin(), wordDict.end());
        int n = s.size();
        bool f[n + 1];
        memset(f, false, sizeof(f));
        f[0] = true;
        for (int i = 1; i <= n; ++i) {
            for (int j = 0; j < i; ++j) {
                if (f[j] && words.count(s.substr(j, i - j))) {
                    f[i] = true;
                    break;
                }
            }
        }
        return f[n];
    }
};