Length of longest non-repeating substring challenge using sliding window












0












$begingroup$


I am working on Leetcode challenge #3 (https://leetcode.com/problems/longest-substring-without-repeating-characters/)



Here is my solution using sliding window and a dictionary. I specifically added start = seen[s[i]]+1 to skip ahead. I am still told I am far slower than most people (for example, given abcdefgdabc, I am skipping abc when I see the second d. I thought this would save ton of time, but apparently this algorithm has a poor run time.



 class Solution(object):
def lengthOfLongestSubstring(self, s):
"""
:type s: str
:rtype: int
"""
seen = {}
start = 0
max_size = 0

# check whether left pointer has reached the end yet
while start < len(s):
size = 0
for i in range(start, len(s)):
if s[i] in seen:
start = seen[s[i]]+1
seen = {}
break
else:
seen[s[i]] = i
size += 1
max_size = max(size, max_size)
return max_size









share|improve this question











$endgroup$

















    0












    $begingroup$


    I am working on Leetcode challenge #3 (https://leetcode.com/problems/longest-substring-without-repeating-characters/)



    Here is my solution using sliding window and a dictionary. I specifically added start = seen[s[i]]+1 to skip ahead. I am still told I am far slower than most people (for example, given abcdefgdabc, I am skipping abc when I see the second d. I thought this would save ton of time, but apparently this algorithm has a poor run time.



     class Solution(object):
    def lengthOfLongestSubstring(self, s):
    """
    :type s: str
    :rtype: int
    """
    seen = {}
    start = 0
    max_size = 0

    # check whether left pointer has reached the end yet
    while start < len(s):
    size = 0
    for i in range(start, len(s)):
    if s[i] in seen:
    start = seen[s[i]]+1
    seen = {}
    break
    else:
    seen[s[i]] = i
    size += 1
    max_size = max(size, max_size)
    return max_size









    share|improve this question











    $endgroup$















      0












      0








      0





      $begingroup$


      I am working on Leetcode challenge #3 (https://leetcode.com/problems/longest-substring-without-repeating-characters/)



      Here is my solution using sliding window and a dictionary. I specifically added start = seen[s[i]]+1 to skip ahead. I am still told I am far slower than most people (for example, given abcdefgdabc, I am skipping abc when I see the second d. I thought this would save ton of time, but apparently this algorithm has a poor run time.



       class Solution(object):
      def lengthOfLongestSubstring(self, s):
      """
      :type s: str
      :rtype: int
      """
      seen = {}
      start = 0
      max_size = 0

      # check whether left pointer has reached the end yet
      while start < len(s):
      size = 0
      for i in range(start, len(s)):
      if s[i] in seen:
      start = seen[s[i]]+1
      seen = {}
      break
      else:
      seen[s[i]] = i
      size += 1
      max_size = max(size, max_size)
      return max_size









      share|improve this question











      $endgroup$




      I am working on Leetcode challenge #3 (https://leetcode.com/problems/longest-substring-without-repeating-characters/)



      Here is my solution using sliding window and a dictionary. I specifically added start = seen[s[i]]+1 to skip ahead. I am still told I am far slower than most people (for example, given abcdefgdabc, I am skipping abc when I see the second d. I thought this would save ton of time, but apparently this algorithm has a poor run time.



       class Solution(object):
      def lengthOfLongestSubstring(self, s):
      """
      :type s: str
      :rtype: int
      """
      seen = {}
      start = 0
      max_size = 0

      # check whether left pointer has reached the end yet
      while start < len(s):
      size = 0
      for i in range(start, len(s)):
      if s[i] in seen:
      start = seen[s[i]]+1
      seen = {}
      break
      else:
      seen[s[i]] = i
      size += 1
      max_size = max(size, max_size)
      return max_size






      python algorithm






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited 9 mins ago







      CppLearner

















      asked 16 mins ago









      CppLearnerCppLearner

      247210




      247210






















          0






          active

          oldest

          votes











          Your Answer





          StackExchange.ifUsing("editor", function () {
          return StackExchange.using("mathjaxEditing", function () {
          StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
          StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["\$", "\$"]]);
          });
          });
          }, "mathjax-editing");

          StackExchange.ifUsing("editor", function () {
          StackExchange.using("externalEditor", function () {
          StackExchange.using("snippets", function () {
          StackExchange.snippets.init();
          });
          });
          }, "code-snippets");

          StackExchange.ready(function() {
          var channelOptions = {
          tags: "".split(" "),
          id: "196"
          };
          initTagRenderer("".split(" "), "".split(" "), channelOptions);

          StackExchange.using("externalEditor", function() {
          // Have to fire editor after snippets, if snippets enabled
          if (StackExchange.settings.snippets.snippetsEnabled) {
          StackExchange.using("snippets", function() {
          createEditor();
          });
          }
          else {
          createEditor();
          }
          });

          function createEditor() {
          StackExchange.prepareEditor({
          heartbeatType: 'answer',
          autoActivateHeartbeat: false,
          convertImagesToLinks: false,
          noModals: true,
          showLowRepImageUploadWarning: true,
          reputationToPostImages: null,
          bindNavPrevention: true,
          postfix: "",
          imageUploader: {
          brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
          contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
          allowUrls: true
          },
          onDemand: true,
          discardSelector: ".discard-answer"
          ,immediatelyShowMarkdownHelp:true
          });


          }
          });














          draft saved

          draft discarded


















          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fcodereview.stackexchange.com%2fquestions%2f214211%2flength-of-longest-non-repeating-substring-challenge-using-sliding-window%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown

























          0






          active

          oldest

          votes








          0






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes
















          draft saved

          draft discarded




















































          Thanks for contributing an answer to Code Review Stack Exchange!


          • Please be sure to answer the question. Provide details and share your research!

          But avoid



          • Asking for help, clarification, or responding to other answers.

          • Making statements based on opinion; back them up with references or personal experience.


          Use MathJax to format equations. MathJax reference.


          To learn more, see our tips on writing great answers.




          draft saved


          draft discarded














          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fcodereview.stackexchange.com%2fquestions%2f214211%2flength-of-longest-non-repeating-substring-challenge-using-sliding-window%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown





















































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown

































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown







          Popular posts from this blog

          Ottavio Pratesi

          Tricia Helfer

          15 giugno