word break

bool wordBreak(string s, unordered_set<string> &dict) {
vector<int> dp(s.size() + 1);  //dp[i + 1]为s(0~i)是否有路径
dp[0] = 1;
for (int i = 1; i < s.size() + 1; i++)
{
int j = i;
while (j >= 0 && dp[i] == 0)
{
if (dp[j] == 1 && dict.find(s.substr(j, i - j)) != dict.end())
dp[i] = 1;
else
j--;
}
}

return dp[s.size()] == 1;
}