Created
September 23, 2020 16:17
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static int speedUp=[](){ | |
std::ios::sync_with_stdio(false); | |
cin.tie(nullptr); | |
cout.tie(nullptr); | |
return 0; | |
}(); | |
class Solution { | |
public: | |
int ladderLength(string beginWord, string endWord, vector<string>& wordList) { | |
unordered_set<string> myset; | |
bool isPresent = false; //Checks if endWord is present in Dict | |
//Insert all words from Dict in myset | |
for(auto word: wordList) | |
{ | |
if(endWord.compare(word)==0) | |
isPresent = true; | |
myset.insert(word); //Insert word in Dict | |
} | |
if(isPresent==false) //endWord is not present in Dict | |
return 0; | |
queue<string> q; | |
q.push(beginWord); | |
int depth = 0; | |
while(!q.empty()) | |
{ | |
depth+=1; | |
int lsize = q.size(); //No of elements at a level | |
while(lsize--) | |
{ | |
string curr = q.front(); | |
q.pop(); | |
//check for all possible 1 depth words | |
for(int i=0;i<curr.length();++i) //For each index | |
{ | |
string temp = curr; | |
for(char c='a';c<='z';++c) //Try all possible chars | |
{ | |
temp[i] = c; | |
if(curr.compare(temp)==0) | |
continue; //Skip the same word | |
if(temp.compare(endWord)==0) | |
return depth+1; //endWord found | |
if(myset.find(temp)!=myset.end()) | |
{ | |
q.push(temp); | |
myset.erase(temp); | |
} | |
} | |
} | |
} | |
} | |
return 0; | |
} | |
}; |
java solution
public class Solution {
public int solve(String beginWord, String endWord, String[] wordList) {
Set myset = new HashSet();
boolean isPresent = false; //Checks if endWord is present in Dict
//Insert all words from Dict in myset
for(String word: wordList)
{
if(endWord.compareTo(word) == 0)
isPresent = true;
myset.add(word); //Insert word in Dict
}
if(isPresent==false) //endWord is not present in Dict
return 0;
Queue<String> q = new LinkedList<>();
q.add(beginWord);
int depth = 0;
while(!q.isEmpty())
{
depth+=1;
int lsize = q.size(); //No of elements at a level
while(lsize-- > 0)
{
String curr = q.poll();
//check for all possible 1 depth words
for(int i=0;i<curr.length();++i) //For each index
{
StringBuilder temp1 = new StringBuilder(curr);
for(char c='a';c<='z';++c) //Try all possible chars
{
temp1.setCharAt(i, c);
String temp = temp1.toString();
if(curr.compareTo(temp) == 0)
continue; //Skip the same word
if(temp.compareTo(endWord) == 0)
return depth+1; //endWord found
if(myset.contains(temp))
{
q.add(temp);
myset.remove(temp);
}
}
}
}
}
return 0;
}
}
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Hey, I think lines 46 to 50 should be swapped with 44 to 45. Because I think we should first check if the word which we are forming exists in the set that we initially created. Doing this lead to a significant reduction in the runtime on leetcode. Please correct me if I am wrong...