use hash table.characters count will be stored on the basis of their ascii value . ie a's count will be stored in array[97] . at last just check the count of each . count==1 gives u the first non repeating character
On Tue, Jul 19, 2011 at 12:31 AM, aditi garg <aditi.garg.6...@gmail.com>wrote: > @sagar ur solution is very gud...bt wat abt blank spaces and capital > alphabets dat may be thr...i dnt think it will take care of that... > > > On Mon, Jul 18, 2011 at 11:32 PM, varun pahwa <varunpahwa2...@gmail.com>wrote: > >> @sagar: that's what i have done i have taken two variables x and y which >> can show if repetition is there or not. and we can store the initial >> positions in the array in that case u don't have to traverse the string >> twice. >> >> >> On Mon, Jul 18, 2011 at 10:33 PM, sagar pareek <sagarpar...@gmail.com>wrote: >> >>> @dumanshu >>> first read my soution just above yours :) >>> >>> On Mon, Jul 18, 2011 at 10:21 PM, Dumanshu <duman...@gmail.com> wrote: >>> >>>> heres my solution with TC O(n) and SC O(26) >>>> input string str >>>> int arr[26] = {0}; >>>> traverse the string, character by character and increment the >>>> corresponding counter. >>>> i.e. arr[str[i]]++; >>>> >>>> Now traverse the string again and print out the first character >>>> encountered whose arr[str[i]] == 1; >>>> >>>> On Jul 18, 9:20 pm, sagar pareek <sagarpar...@gmail.com> wrote: >>>> > Very good solution :- but space complexity = O(26) >>>> > >>>> > take integer array arr[0-25] and initialise it with 0 by taking it >>>> static >>>> > logic is that we have only 26 characters so if i want to map character >>>> 'a' >>>> > with 0th position of arr[] then it can be done as atoi('a')-97. >>>> > so whenever we encounter any character say str[i] (where str is array >>>> of >>>> > given string) then it can be incremented as arr[atoi(str[i])-97]++ >>>> > so traverse the whole str[] and increment the corresponding values . >>>> > At the end those characters which never encounter have values 0 in arr >>>> , >>>> > which encounter only once have values 1 and more than once have >>>> values>1. >>>> > at the end traverse the whole arr[] and find out the corresponding >>>> character >>>> > as itoa(arr[i]+97) :) :) >>>> > >>>> > But we have to do extra work to find the first character which repeats >>>> only >>>> > once >>>> > >>>> > On Mon, Jul 18, 2011 at 8:09 PM, hary rathor <harry.rat...@gmail.com> >>>> wrote: >>>> > > can we use bit vector ? >>>> > > because by do it we need just 32 bits of one extra variable . >>>> > >>>> > > -- >>>> > > You received this message because you are subscribed to the Google >>>> Groups >>>> > > "Algorithm Geeks" group. >>>> > > To post to this group, send email to algogeeks@googlegroups.com. >>>> > > To unsubscribe from this group, send email to >>>> > > algogeeks+unsubscr...@googlegroups.com. >>>> > > For more options, visit this group at >>>> > >http://groups.google.com/group/algogeeks?hl=en. >>>> > >>>> > -- >>>> > **Regards >>>> > SAGAR PAREEK >>>> > COMPUTER SCIENCE AND ENGINEERING >>>> > NIT ALLAHABAD >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Algorithm Geeks" group. >>>> To post to this group, send email to algogeeks@googlegroups.com. >>>> To unsubscribe from this group, send email to >>>> algogeeks+unsubscr...@googlegroups.com. >>>> For more options, visit this group at >>>> http://groups.google.com/group/algogeeks?hl=en. >>>> >>>> >>> >>> >>> -- >>> **Regards >>> SAGAR PAREEK >>> COMPUTER SCIENCE AND ENGINEERING >>> NIT ALLAHABAD >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "Algorithm Geeks" group. >>> To post to this group, send email to algogeeks@googlegroups.com. >>> To unsubscribe from this group, send email to >>> algogeeks+unsubscr...@googlegroups.com. >>> For more options, visit this group at >>> http://groups.google.com/group/algogeeks?hl=en. >>> >> >> >> >> -- >> Varun Pahwa >> B.Tech (IT) >> 7th Sem. >> Indian Institute of Information Technology Allahabad. >> Ph : 09793899112 >> Official Email :: rit2008...@iiita.ac.in >> Another Email :: varunpahwa.ii...@gmail.com >> >> People who fail to plan are those who plan to fail. >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Algorithm Geeks" group. >> To post to this group, send email to algogeeks@googlegroups.com. >> To unsubscribe from this group, send email to >> algogeeks+unsubscr...@googlegroups.com. >> For more options, visit this group at >> http://groups.google.com/group/algogeeks?hl=en. >> > > > > -- > Aditi Garg > Undergraduate Student > Electronics & Communication Divison > NETAJI SUBHAS INSTITUTE OF TECHNOLOGY > Sector 3, Dwarka > New Delhi > > 9718388816 > > -- > You received this message because you are subscribed to the Google Groups > "Algorithm Geeks" group. > To post to this group, send email to algogeeks@googlegroups.com. > To unsubscribe from this group, send email to > algogeeks+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/algogeeks?hl=en. > -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. 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