1259. Handshakes That Don’t Cross
You are given an even number of people numPeople that stand around a circle and each person shakes hands with someone else so that there are numPeople / 2 handshakes total.
Return the number of ways these handshakes could occur such that none of the handshakes cross.
Since the answer could be very large, return it modulo 109 + 7.
452. Minimum Number of Arrows to Burst Balloons
There are some spherical balloons taped onto a flat wall that represents the XY-plane. The balloons are represented as a 2D integer array points where points[i] = [xstart, xend] denotes a balloon whose horizontal diameter stretches between xstart and xend. You do not know the exact y-coordinates of the balloons.
Arrows can be shot up directly vertically (in the positive y-direction) from different points along the x-axis. A balloon with xstart and xend is burst by an arrow shot at x if xstart <= x <= xend. There is no limit to the number of arrows that can be shot. A shot arrow keeps traveling up infinitely, bursting any balloons in its path.
Given the array points, return the minimum number of arrows that must be shot to burst all balloons.
Given the array houses where houses[i] is the location of the ith house along a street and an integer k, allocate k mailboxes in the street.
Return the minimum total distance between each house and its nearest mailbox.
The test cases are generated so that the answer fits in a 32-bit integer.
363. Max Sum of Rectangle No Larger Than K
Given an m x n matrix matrix and an integer k, return the max sum of a rectangle in the matrix such that its sum is no larger than k.
It is guaranteed that there will be a rectangle with a sum no larger than k.
1751. Maximum Number of Events That Can Be Attended II
You are given an array of events where events[i] = [startDayi, endDayi, valuei]. The ith event starts at startDayi and ends at endDayi, and if you attend this event, you will receive a value of valuei. You are also given an integer k which represents the maximum number of events you can attend.
You can only attend one event at a time. If you choose to attend an event, you must attend the entire event. Note that the end day is inclusive: that is, you cannot attend two events where one of them starts and the other ends on the same day.
Return the maximum sum of values that you can receive by attending events.
1060. Missing Element in Sorted Array
Given an integer array nums which is sorted in ascending order and all of its elements are unique and given also an integer k, return the kth missing number starting from the leftmost number of the array.
1235. Maximum Profit in Job Scheduling
We have n jobs, where every job is scheduled to be done from startTime[i] to endTime[i], obtaining a profit of profit[i].
You’re given the startTime, endTime and profit arrays, return the maximum profit you can take such that there are no two jobs in the subset with overlapping time range.
If you choose a job that ends at time X you will be able to start another job that starts at time X.
1151. Minimum Swaps to Group All 1’s Together
Given a binary array data, return the minimum number of swaps required to group all 1’s present in the array together in any place in the array.
A peak element in a 2D grid is an element that is strictly greater than all of its adjacent neighbors to the left, right, top, and bottom.
Given a 0-indexed m x n matrix mat where no two adjacent cells are equal, find any peak element mat[i][j] and return the length 2 array [i,j].
You may assume that the entire matrix is surrounded by an outer perimeter with the value -1 in each cell.
You must write an algorithm that runs in O(m log(n)) or O(n log(m)) time.
828. Count Unique Characters of All Substrings of a Given String
Let’s define a function countUniqueChars(s) that returns the number of unique characters on s.
- For example, calling countUniqueChars(s) if s = “LEETCODE” then “L”, “T”, “C”, “O”, “D” are the unique characters since they appear only once in s, therefore countUniqueChars(s) = 5.
Given a string s, return the sum of countUniqueChars(t) where t is a substring of s.
Notice that some substrings can be repeated so in this case you have to count the repeated ones too.