摘要：
核心： pre[i][j] 为节点 i 向上2的j次方处的祖先。 pre[i][j] = pre[pre[i][j-1]][j-1] 阅读全文
摘要：
Anniversary party Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 8261 Accepted: 4742 Description There is going to be a party to celebrate 阅读全文