Find the index of the first occurrence in a string | Leetcode 28

Find the index of the first occurrence in a string
Leetcode problem number 28

JAVA interview programming playlist:

#java #interviewquestions #leetcode

[shreyasjain]

class Solution {
public int strStr(String haystack, String needle) {
if (haystack.contains(needle)) {
return haystack.indexOf(needle);
} else {
return -1;
}
}
}

[RishinderRana]

This isn't an efficient solution. The complexity can be reduced to O(m + n) using KMP. Giving this answer may not fail you in the interview though but will not get you the best score either.

[BlendBox]

Hey,

Thank you so much for now, I solve the problem of LeetCode, nice explanation 😊

[sangameshwar]

Very useful content for Learning please subscribe and like share guys ❤😊😊

[arafathossain]

Can you solve this problem with robin carp rolling hash?

[DevbrathBhattPujari]

Can you please explain more at timestamp 4:45 that why did you not take the whole length and just till index 7?

[DevbrathBhattPujari]

Can you please explain more at timestamp 4:45 that why did you just took the string till index 7?

[kumar_shanu]

You are doing a great job, keep it up, but its a request please try to include the most efficient approach, like KMP algorithm thats required here with space and time complexity.

[AkashSharmaSDE]

very easy and helpful but Mam its time is O(m*n).Is there any other method in JS for O(m+n)?

[vikaspathak]

class Solution {
public int strStr(String haystack, String needle) {
return haystack.indexOf(needle);
}
}

single line code for this problem

[madhur]

smooth explanation
it would be helpelful if you can discuss time and space complexity with the approach.

[rishabhduggar]

this code will fail for the following input: haystack="hello" and needle = "ll"
if we do needle.length+1 then (i, needle.length)+1 will not give the correct substring as it will go from (2, 5)
it will include the last character as well "llo" which will result in wrong output
please correct me if i am wrong...

[saurabhtiwari]

great explanation! Thanks for the help

[MindsetMotivation]

Thank you for this amazing explanation

[shanayagupta]

same approach i used in leetcode but it will give TLE for sure

[chakravarthybatna]

you are doing great work but please try to come up with at least 2 approaches like one will be brute force and other will be the optimal solution

[TharunReddy]

this is of O(mn) complexity, any other optimized solution?

[harnekarora]

Explanation was nice but can we use methods like .charAt(), .substring() or .indexOf() in leetcode ?? Did you try entering this solution in leetcode . It doesn't work

[sandeepnarwal]

Hey can anyone explain me how does "sad" comes at 0th index of "sadbutsad" word? Thanks

[SanjayChandramohan-lqwp]

This logic fails when haystack.length is less than needle's