Leetcode-longest Substring without repeating characters

Longest Substring without repeating characters

Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters for "ABCABCBB" are "abc", which the length is 3. For "bbbbb" the longest substring are "B", with the length of 1.

Find the longest string of different substrings

Null length is 0 direct return 0

Length of 1, return 1

For cases greater than 1

To traverse a string:

Define a HashSet collection

For each element in the string, if it does not exist in the collection, join the collection

If it already exists in the collection: Assuming that this element is CH, to remove all elements that precede the set CH, left plus a

 while (S.charat (left)! =ch) {                    set.remove (S.charat (left));                    left + +;                } // End While                left++;

That's the main procedure.

All Programs

 Public classSolution { Public intlengthoflongestsubstring (String s) {HashSet set=NewHashSet (); intleft = 0; intright = 0; intMax = 0; Charch; if(s==NULL&& s.length () ==0)return0; if(S.length () ==1)return1;  for(Right=0;right<s.length (); right++) {ch=S.charat (right); if(Set.contains (ch)) {Max=math.max (max,right-Left );  while(S.charat (left)! =ch)                    {Set.remove (S.charat (left)); Left++; }//End Whileleft++; }Else{set.add (ch); // Right}//End If}//End formax = Math.max (max,right-Left ); returnMax; }//End}

Python program, not read

classsolution (object):deflengthoflongestsubstring (self, s):""": Type S:str:rtype:int"""        ifLen (s) ==0:return0ifLen (s) ==1:return1Lastapppos={s[0]:0}#Last appear position of AlphabetLongestendinghere=[1]*len (s)#longest substring ending here         forIndexinchXrange (1, Len (s)): Lastpos= Lastapppos.get (s[index],-1)            ifLastpos<index-longestendinghere[index-1]: Longestendinghere[index]= Longestendinghere[index-1] + 1Else: Longestendinghere[index]= Index-Lastpos Lastapppos[s[index]]=IndexreturnMax (Longestendinghere)

Leetcode-longest Substring without repeating characters