摘要：
You have some sticks with positive integer lengths. You can connect any two sticks of lengths X and Y into one stick by paying a cost of X + Y. You pe 阅读全文
摘要：
Given a non-empty 2D array grid of 0's and 1's, an island is a group of 1's (representing land) connected 4-directionally (horizontal or vertical.) Yo 阅读全文