//If there is no '&' before set, the time cost will be tripled;
int ladderLength(unordered_set<string>& bList, unordered_set<string>& eList, unordered_set<string>& wordList, int len)
{
if(bList.empty())
return 0;
if(bList.size() > eList.size())
return ladderLength(eList, bList, wordList, len);
unordered_set<string> tmpList;
for(auto it=bList.begin(); it!=bList.end(); it++)
{
string cur = *it;
for(int i=0; i<cur.size(); i++)
{
char c0 = cur[i];
for(char c='a'; c<='z'; c++)
{
cur[i]=c;
if(eList.count(cur)) return len+1;
if(wordList.count(cur))
{
tmpList.insert(cur);
wordList.erase(cur);
}
}
cur[i] = c0;
}
}
return ladderLength(tmpList, eList, wordList, len+1);
}
int check(string beginWord, string endWord, unordered_set<string> wordList)
{
if(beginWord == endWord) return 2;
auto n = wordList.find(beginWord);
if(n != wordList.end()) wordList.erase(n);
int res = 9999;
for (int i = 0; i < beginWord.size(); ++i)
{
string s = beginWord;
for(char j = 'a'; j <= 'z'; j++)
{
s[i] = j;
if(s == endWord) return 2;
auto pos = wordList.find(s);
if (pos != wordList.end())
{
wordList.erase(pos);
res = min(res,ladderLength(s,endWord,wordList));
}
}
}
return res;
}
vector<vector<string> > findLadders(string start, string end, unordered_set<string> &dict) {
unordered_map<string, vector<string*> > prev;
int len = ladderLength(start, end, dict, prev);
vector<vector<string> > result;
vector<string*> path;
setResult(start, end, prev, path, result);
return result;
}
TEST(WordLadderTest, T1) {
std::string output;
testing::internal::CaptureStdout();
std::vector<std::string> wordList{ "hot","dot","dog","lot","log" };
auto result = ladderLength("hit", "cog", wordList);
output = testing::internal::GetCapturedStdout();
ASSERT_EQ(0, result);
}
vector<vector<string> > findLaddersII(string start, string end, unordered_set<string> &dict) {
vector<vector<string> > result;
vector<string> ret;
int minLen = ladderLength(start, end, dict);
if (!minLen) {
return result;
}
ret.push_back(start);
dfs(ret, minLen, end, dict, result);
return result;
}
int ladderLength(string bWord, string eWord, unordered_set<string>& wordList)
{
if(bWord == eWord)
return 1;
unordered_set<string> bList, eList;
bList.insert(bWord);
eList.insert(eWord);
wordList.erase(bWord);
wordList.erase(eWord);
return ladderLength(bList, eList, wordList, 1);
}
/*
int ladderLength(string start, string end, unordered_set<string> & dict)
{
if(start.size() != end.size()) return 0;
if(isConnect(start, end)) return 2;
int res = dict.size() + 3;
for (std::unordered_set<string>::iterator itr = dict.begin(); itr != dict.end(); ++itr)
{
if(isConnect(start, *itr))
{
unordered_set<string> tem = dict;
tem.erase(*itr);
int t = ladderLength(*itr, end, tem);
if(t != 0) res = min(res, 1 + t);
}
}
if(res == dict.size() + 3) return 0;
return res;
}
*/
int main(int argc, char const *argv[])
{
string start = "hit";
string end = "cog";
unordered_set<string> dict = {"hot","cog","dot","dog","hit","lot","log"};
cout<<start <<endl <<end<<endl;
for (std::unordered_set<string>::iterator i = dict.begin(); i != dict.end(); ++i)
{
cout<<*i<<",";
}
cout<<endl;
cout<<ladderLength(start, end, dict)<<endl;
return 0;
}
