Leetcode on Saltfish's Blog

The Number of Good Subsets

Fri, 20 Feb 2026 16:22:49 -0500

Problem #

You are given an integer array nums. We call a subset of nums good if its product can be represented as a product of one or more distinct prime numbers.

For example, if nums = [1, 2, 3, 4]:
[2, 3], [1, 2, 3], and [1, 3] are good subsets with products 6 = 2*3, 6 = 2*3, and 3 = 3 respectively.
[1, 4] and [4] are not good subsets with products 4 = 2*2 and 4 = 2*2 respectively.
Return the number of different good subsets in nums modulo 1e9 + 7.

Merge Two Binary Tree

Sat, 14 Feb 2026 19:04:39 -0500

Link Merge Two Binary Trees

Problem #

You are given two binary trees root1 and root2.

Imagine that when you put one of them to cover the other, some nodes of the two trees are overlapped while the others are not. You need to merge the two trees into a new binary tree. The merge rule is that if two nodes overlap, then sum node values up as the new value of the merged node. Otherwise, the NOT null node will be used as the node of the new tree.

Stone Game

Fri, 13 Feb 2026 19:46:40 -0500

Link: Stone Game

Problem #

Alice and Bob play a game with piles of stones. There are an even number of piles arranged in a row, and each pile has a positive integer number of stones piles[i].

The objective of the game is to end with the most stones. The total number of stones across all the piles is odd, so there are no ties.

Split a String in Balanced Strings

Thu, 12 Feb 2026 18:06:47 -0500

Problem Link: Split a String in Balanced Strings

Problem #

Balanced strings are those that have an equal quantity of ‘L’ and ‘R’ characters.

Given a balanced string s, split it into some number of substrings such that:

Each substring is balanced. Return the maximum number of balanced strings you can obtain.

Stone Game II

Wed, 11 Feb 2026 16:57:25 -0500

Stone Game II #

Link: Stone Game II

Problem #

Alice and Bob continue their games with piles of stones. There are a number of piles arranged in a row, and each pile has a positive integer number of stones piles[i]. The objective of the game is to end with the most stones.