An integer array is called arithmetic if it consists of at least three elements and if the difference between any two consecutive elements is the same.
- For example, [1,3,5,7,9], [7,7,7,7], and [3,-1,-5,-9] are arithmetic sequences.
Given an integer array nums, return the number of arithmetic subarrays of nums.
A subarray is a contiguous subsequence of the array.
There is a group of n people labeled from 0 to n - 1 where each person has a different amount of money and a different level of quietness.
You are given an array richer where richer[i] = [ai, bi] indicates that ai has more money than bi and an integer array quiet where quiet[i] is the quietness of the ith person. All the given data in richer are logically correct (i.e., the data will not lead you to a situation where x is richer than y and y is richer than x at the same time).
Return an integer array answer where answer[x] = y if y is the least quiet person (that is, the person y with the smallest value of quiet[y]) among all people who definitely have equal to or more money than the person x.
2019. The Score of Students Solving Math Expression
You are given a string s that contains digits 0-9, addition symbols ‘+’, and multiplication symbols ‘‘ only, representing a valid math expression of single digit numbers (e.g., 3+52). This expression was given to n elementary school students. The students were instructed to get the answer of the expression by following this order of operations:
- Compute multiplication, reading from left to right; Then,
- Compute addition, reading from left to right.
You are given an integer array answers of length n, which are the submitted answers of the students in no particular order. You are asked to grade the answers, by following these rules:
If an answer equals the correct answer of the expression, this student will be rewarded 5 points;
Otherwise, if the answer could be interpreted as if the student applied the operators in the wrong order but had correct arithmetic, this student will be rewarded 2 points;
- Otherwise, this student will be rewarded 0 points.
Return the sum of the points of the students.
We can scramble a string s to get a string t using the following algorithm:
- If the length of the string is 1, stop.
- If the length of the string is > 1, do the following:
- Split the string into two non-empty substrings at a random index, i.e., if the string is s, divide it to x and y where s = x + y.
- Randomly decide to swap the two substrings or to keep them in the same order. i.e., after this step, s may become s = x + y or s = y + x.
- Apply step 1 recursively on each of the two substrings x and y.
Given two strings s1 and s2 of the same length, return true if s2 is a scrambled string of s1, otherwise, return false.
2167. Minimum Time to Remove All Cars Containing Illegal Goods
You are given a 0-indexed binary string s which represents a sequence of train cars. s[i] = ‘0’ denotes that the ith car does not contain illegal goods and s[i] = ‘1’ denotes that the ith car does contain illegal goods.
As the train conductor, you would like to get rid of all the cars containing illegal goods. You can do any of the following three operations any number of times:
- Remove a train car from the left end (i.e., remove s[0]) which takes 1 unit of time.
- Remove a train car from the right end (i.e., remove s[s.length - 1]) which takes 1 unit of time.
- Remove a train car from anywhere in the sequence which takes 2 units of time.
Return the minimum time to remove all the cars containing illegal goods.
Note that an empty sequence of cars is considered to have no cars containing illegal goods.
2163. Minimum Difference in Sums After Removal of Elements
You are given a 0-indexed integer array nums consisting of 3 * n elements.
You are allowed to remove any subsequence of elements of size exactly n from nums. The remaining 2 * n elements will be divided into two equal parts:
- The first n elements belonging to the first part and their sum is sumfirst.
- The next n elements belonging to the second part and their sum is sumsecond.
The difference in sums of the two parts is denoted as sumfirst - sumsecond.
- For example, if sumfirst = 3 and sumsecond = 2, their difference is 1.
- Similarly, if sumfirst = 2 and sumsecond = 3, their difference is -1.
Return the minimum difference possible between the sums of the two parts after the removal of n elements.
2161. Partition Array According to Given Pivot
You are given a 0-indexed integer array nums and an integer pivot. Rearrange nums such that the following conditions are satisfied:
- Every element less than pivot appears before every element greater than pivot.
- Every element equal to pivot appears in between the elements less than and greater than pivot.
- The relative order of the elements less than pivot and the elements greater than pivot is maintained.
- More formally, consider every pi, pj where pi is the new position of the ith element and pj is the new position of the jth element. For elements less than pivot, if i < j and nums[i] < pivot and nums[j] < pivot, then pi < pj. Similarly for elements greater than pivot, if i < j and nums[i] > pivot and nums[j] > pivot, then pi < pj.
Return nums after the rearrangement.
2165. Smallest Value of the Rearranged Number
You are given an integer num. Rearrange the digits of num such that its value is minimized and it does not contain any leading zeros.
Return the rearranged number with minimal value.
Note that the sign of the number does not change after rearranging the digits.
448. Find All Numbers Disappeared in an Array
Given an array nums of n integers where nums[i] is in the range [1, n], return an array of all the integers in the range [1, n] that do not appear in nums.
350. Intersection of Two Arrays II
Given two integer arrays nums1 and nums2, return an array of their intersection. Each element in the result must appear as many times as it shows in both arrays and you may return the result in any order.