摘要：
Given an array points where points[i] = [xi, yi] represents a point on the X-Y plane, return true if these points are a boomerang. A boomerang is a se 阅读全文
摘要：
Given the root of a binary tree, return the number of nodes where the value of the node is equal to the sum of the values of its descendants. A descen 阅读全文