摘要：
You are given a line of nn colored squares in a row, numbered from 11 to nn from left to right. The ii-th square initially has the color cici. Let's s 阅读全文
摘要：
The lowest common ancestor (LCA) of two nodes U and V in a tree is the deepest node that has both U and V as descendants. Given any two nodes in a bin 阅读全文