摘要： Given a binary tree Populate each next pointer to point to its next right node. If there is no next right node, the next pointer should be set to NULL 阅读全文

摘要： Given an array nums of integers, you can perform operations on the array. In each operation, you pick any nums[i] and delete it to earn nums[i] points 阅读全文

摘要： Given a 2D board and a word, find if the word exists in the grid. The word can be constructed from letters of sequentially adjacent cell, where "adjac 阅读全文