With the increasing seniority in software development, comes up with multiple tasks to manage. I used to struggle between different meetings, completing my tasks, addressing the team’s issues and ad hoc productions bugs. Time used to fly like anything with very less productivity.
Some startups I worked with, did not have a proper tool for bug tracking. They used to create tasks in Google Document or assign bugs on Slack. This created a lot of chaos with no visibility on my work progress. End of the day I did not get the satisfaction of the work being done. …
Problem statement
Implement strStr().
Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.
Clarification:
What should we return when needle is an empty string? This is a great question to ask during an interview.
For the purpose of this problem, we will return 0 when needle is an empty string. This is consistent to C’s strstr() and Java’s indexOf().
Problem statement taken from: https://leetcode.com/problems/implement-strstr
Example 1:
Input: haystack = "hello", needle = "ll"
Output: 2Example 2:
Input: haystack = "aaaaa", needle = "bba"
Output: -1Example 3:
Input: haystack =…
Problem statement
You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and nums2 respectively.
Merge nums1 and nums2 into a single array sorted in non-decreasing order.
The final sorted array should not be returned by the function, but instead, be stored inside the array nums1. To accommodate this, nums1 has a length of m + n, where the first m elements denote the elements that should be merged, and the last n elements are set to 0 and should be ignored. …
Problem statement
Given an array nums with n objects colored red, white, or blue, sort them in-place so that objects of the same color are adjacent, with the colors in the order red, white, and blue.
We will use the integers 0, 1, and 2 to represent the color red, white, and blue, respectively.
You must solve this problem without using the library’s sort function.
Problem statement taken from: https://leetcode.com/problems/sort-colors
Example 1:
Input: nums = [2, 0, 2, 1, 1, 0]
Output: [0, 0, 1, 1, 2, 2]Example 2:
Input: nums = [2, 0, 1]
Output: [0, 1, 2]Example 3:
…
Problem statement
Given a string s containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[‘ and ‘]’, determine if the input string is valid.
An input string is valid if:
1. Open brackets must be closed by the same type of brackets.
2. Open brackets must be closed in the correct order.Problem statement taken from: https://leetcode.com/problems/valid-parentheses
Example 1:
Input: s = "()"
Output: trueExample 2:
Input: s = "()[]{}"
Output: trueExample 3:
Input: s = "(]"
Output: falseExample 4:
Input: s = "([)]"
Output: falseExample 5:
Input: s = "{[]}"
Output: trueConstraints:
- 1 <= s.length…
Problem statement
You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise).
You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation.
Problem statement taken from: https://leetcode.com/problems/rotate-image
Example 1:
Input: matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
Output: [[7, 4, 1], [8, 5, 2], [9, 6, 3]]Example 2:
Input: matrix = [[5, 1, 9, 11], [2, 4, 8, 10], [13, 3, 6, 7], [15, 14, 12, 16]]
Output: [[15, 13, 2…
Problem statement
Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.
Problem statement taken from: https://leetcode.com/problems/maximum-subarray
Example 1:
Input: nums = [-2, 1, -3, 4, -1, 2, 1, -5, 4]
Output: 6
Explanation: [4, -1, 2, 1] has the largest sum = 6.Example 2:
Input: nums = [1]
Output: 1Example 3:
Input: nums = [5, 4, -1, 7, 8]
Output: 23Constraints:
- 1 <= nums.length <= 3 * 10^4 -
-10^5 <= nums[i] <= 10^5Explanation
Brute force
The brute force approach is to generate all subarrays and…
Problem statement
Given an array of integers nums sorted in ascending order, find the starting and ending position of a given target value.
If target is not found in the array, return [-1, -1].
Problem statement taken from: https://leetcode.com/problems/find-first-and-last-position-of-element-in-sorted-array
Example 1:
Input: nums = [5, 7, 7, 8, 8, 10], target = 8
Output: [3, 4]Example 2:
Input: nums = [5, 7, 7, 8, 8, 10], target = 6
Output: [-1, -1]Example 3:
Input: nums = [], target = 0
Output: [-1, -1]Constraints:
- 0 <= nums.length <= 10^5
- -10^9 <= nums[i] <= 10^9
- nums is a non-decreasing array.
…
Problem statement
Given a sorted array nums, remove the duplicates in-place such that each element appears only once and returns the new length.
Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.
Problem statement taken from: https://leetcode.com/problems/remove-duplicates-from-sorted-array
Example 1:
Input: nums = [1, 1, 2]
Output: 2, nums = [1, 2]
Explanation: Your function should return length = 2, with the first two elements of nums being 1 and 2 respectively. It doesn't matter what you leave beyond the returned length.Example 2:
Input: nums = [0, 0, 1…
Problem statement
Given a non-negative integer x, compute and return the square root of x.
Since the return type is an integer, the decimal digits are truncated, and only the integer part of the result is returned.
Note: You are not allowed to use any built-in exponent function or operator, such as pow(x, 0.5) or x ** 0.5.
Problem statement taken from: https://leetcode.com/problems/sqrtx
Example 1:
Input: x = 4
Output: 2Example 2:
Input: x = 8
Output: 2
Explanation: The square root of 8 is 2.82842..., and since the decimal part is truncated, 2 is returned.Constraints:
0 <= x <=…
