3404. Count Special Subsequences
Point: Turn multiplication to fraction Hard to realize “for r in range(4, n – 2): q = r – 2” part.
Category: LeetCode
Solutions and Insights for LeetCode Problems
2168. Unique Substrings With Equal Digit Frequency
Actually, brute force can work due to constrains. However, if we count the frequency every time, the time complexity will be O(n**3), which may…
1427. Perform String Shifts
Don’t forget mod when dealing with shifting. A negative number a: a % b = (a + b) % b Anyway, easy makes me…
3408. Design Task Manager
Point is: we don’t have to remove items immediately from heap after rmv / edit operation. Do it when we are going to execTop.
3407. Substring Matching Pattern
This easy is easier than yesterday’s easy. New tech: str.find(sub) / str.rfind(sub). find the first/last index of sub. if sub == “”, return 0/n;…
3411. Maximum Subarray With Equal Products
You are given an array of positive integers nums. An array arr is called product equivalent if prod(arr) == lcm(arr) * gcd(arr), where: prod(arr)…