摘要：
A child is running up a staircase with n steps, and can hop either 1 step, 2 steps, or 3 steps at a time. Implement a method to count how many possibl 阅读全文
摘要：
Given two rectangles, find if the given two rectangles overlap or not. Notice l1: Top Left coordinate of first rectangle.r1: Bottom Right coordinate o 阅读全文