dexterpuru/leetcode_java

Archive for Leetcode solutions in Java

Leetcode solutions in Java

Kindly checkout the problemStatementList.md for the current stock of problem statements.

Contributions are always welcome. Kindly checkout CONTRIBUTING.md.

Contributors ❤️

leetcode_java's Issues

Add solution for 'Permutation in String' problem

https://leetcode.com/problems/permutation-in-string/

I'd like to work on this issue. Kindly assign it to me.

Add solution for 'Add Two Numbers II' problem

https://leetcode.com/problems/add-two-numbers-ii/

I'd like to work on this issue. Kindly assign it to me.

Add Solution for "Minimum Path Sum"

Dynamic Programming:
https://leetcode.com/problems/minimum-path-sum

Add solution : JumpGate

https://leetcode.com/problems/jump-game/
label - Hacktoberfest2020

Add Solution for "Evaluate Division"

https://leetcode.com/problems/evaluate-division/
I would like to work on this problem. Please assign it to me

Add String to integer (atoi)

Implement atoi which converts a string to an integer.

The function first discards as many whitespace characters as necessary until the first non-whitespace character is found. Then, starting from this character, takes an optional initial plus or minus sign followed by as many numerical digits as possible, and interprets them as a numerical value.

The string can contain additional characters after those that form the integral number, which are ignored and have no effect on the behavior of this function.

If the first sequence of non-whitespace characters in str is not a valid integral number, or if no such sequence exists because either str is empty or it contains only whitespace characters, no conversion is performed.

If no valid conversion could be performed, a zero value is returned.

Note:

• Only the space character ' ' is considered as whitespace character.

• Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−2³¹, 2³¹ − 1]. If the numerical value is out of the range of representable values, INT_MAX (2³¹ − 1) or INT_MIN (−2³¹) is returned.

Example 1:

Input: 42
Ouput: 42

Example 2:

Input: " -42"
Output: -42
Explanation: The first non-whitespace character is '-', which is the minus sign. Then take as many numerical digits as possible, which gets 42.

Example 3:

Input: "4193 with words"
Output: 4193
Explanation: Conversion stops at digit '3' as the next character is not a numerical digit.

Example 4:

Input: "words and 987"
Output : 0
Explanation: The first non-whitespace character is 'w', which is not a numerical digit or a +/- sign. Therefore no valid conversion could be performed.

Example 5:

Input : "-91283472332"
Output: -2147483648
Explanation: The number "-91283472332" is out of the range of a 32-bit signed integer. Therefore INT_MIN (−2³¹) is returned.

Course Schedule

https://leetcode.com/problems/course-schedule

Please assign this issue to me.

Need leetcode solutions in Java

It would be great if someone could contribute few solutions for leetcode questions.

Few things you need to know:-

1. It doesn't matter if the solution you give is not yours.
2. Code must be clean and understandable.
3. You need to write the approach in comments before writing solutions for understandability.
4. If you want to submit a solution for any new topic whose folder is not there, lets say graph, and if there is not any folder for graph, you will need to make a folder.

This repo is for Java solutions, you can also contribute Solutions in Python and C++here:-
Python - https://github.com/dexterpuru/leetcode_python
C++ - https://github.com/dexterpuru/leetcode_cpp

Add code for Longest Palindromic Substring

Leetcode link: 5. Longest Palindromic Substring

I'd like to work on this issue. Kindly assign it to me.

Intersection of 2 linked list

Question Link
https://leetcode.com/problems/intersection-of-two-linked-lists/

Sum of Even Numbers after Queries

https://leetcode.com/problems/sum-of-even-numbers-after-queries/

We have an array A of integers, and an array queries of queries.

For the i-th query val = queries[i][0], index = queries[i][1], we add val to A[index]. Then, the answer to the i-th query is the sum of the even values of A.

(Here, the given index = queries[i][1] is a 0-based index, and each query permanently modifies the array A.)

Return the answer to all queries. Your answer array should have answer[i] as the answer to the i-th query.

Group Anagram

https://leetcode.com/problems/group-anagrams/

Detect Capital Question

Question Link
https://leetcode.com/problems/detect-capital/

Please assign the hacktober2020 label to it.

Add 'All Possible Full Binary Trees'

Leetcode Link: https://leetcode.com/problems/all-possible-full-binary-trees/

Add 'Friends Of Appropriate Ages'

Leetcode Link: https://leetcode.com/problems/friends-of-appropriate-ages/

48. Rotate Image

Question Link
https://leetcode.com/problems/rotate-image/

Add solution for Add Two Numbers problem

https://leetcode.com/problems/add-two-numbers/

I'd like to work on this issue. Kindly assign it to me.

Add 'Boats to Save People'

Leetcode Link: https://leetcode.com/problems/boats-to-save-people/

Add code to find all anagrams in a string

Leetcode link: 438. Find All Anagrams in a String

I'd like to work on this issue. Kindly assign it to me.

Add 'Reverse Integer'

Leetcode Link: https://leetcode.com/problems/reverse-integer/

Working on this issue.

Add Solution for "Maximum Depth of N-ary Tree"

Depth-first Search
https://leetcode.com/problems/maximum-depth-of-n-ary-tree/

Add solution : 3Sum

https://leetcode.com/problems/3sum/

Add 'Range Sum Query - Immutable'

https://leetcode.com/problems/range-sum-query-immutable/

Add AsteroidCollision Problem

Question Link
https://leetcode.com/problems/asteroid-collision/

We are given an array asteroids of integers representing asteroids in a row.

For each asteroid, the absolute value represents its size, and the sign represents its direction (positive meaning right, negative meaning left). Each asteroid moves at the same speed.

Find out the state of the asteroids after all collisions. If two asteroids meet, the smaller one will explode. If both are the same size, both will explode. Two asteroids moving in the same direction will never meet.

Add solution for 'Number of Recent Calls'

https://leetcode.com/problems/number-of-recent-calls/

Please assign it to me

Add Solution for "Best Time to Buy and Sell Stock"

Dynamic Programming:
https://leetcode.com/problems/best-time-to-buy-and-sell-stock

Add 'Find and Replace Pattern'

Leetcode Link: https://leetcode.com/problems/find-and-replace-pattern/

Design HashSet

Question Link
https://leetcode.com/problems/design-hashset/

Please assign the hacktober2020 label to it.

Add 'Two Sum'

Leetcode Link: https://leetcode.com/problems/two-sum/

11. Container With Most Water

Question Link
https://leetcode.com/problems/container-with-most-water/

Add Longest substring without repeating characters

Given a string s, find the length of the longest substring without repeating characters.

Example 1:

Input: s = "abcabcbb"
Output: 3
Explanation: The answer is "abc", with the length of 3.

Example 2:

Input: s = "bbbbb"
Output: 1
Explanation: The answer is "b", with the length of 1.

Example 3:

Input: s = "pwwkew"
Output: 3
Explanation: The answer is "wke", with the length of 3. Notice that the answer must be a substring, "pwke" is a subsequence and not a substring.

Example 4:

Input: s = ""
Output: 0

Constraints:

0 <= s.length <= 5 * 10⁴
s consists of English letters, digits, symbols and spaces.

Add Solution for "Teemo Attacking"

https://leetcode.com/problems/teemo-attacking/
I would like to work on this problem. Please assign it to me.

Add solution for 'Subarray Product Less Than K'

https://leetcode.com/problems/subarray-product-less-than-k/
I would like to work on this problem, please assign it to me

Add Solution for "Largest Number"

https://leetcode.com/problems/largest-number/
I would like to work on this problem. Please assign it to me

Add solution for "Power of Two"

https://leetcode.com/problems/power-of-two/