Warning: session_start(): open(/tmp/sess_bf185dabefa54cf94085663f2a74c2ed, O_RDWR) failed: No space left on device (28) in /data/wiki/inc/init.php on line 239

Warning: session_start(): Failed to read session data: files (path: ) in /data/wiki/inc/init.php on line 239

Warning: Cannot modify header information - headers already sent by (output started at /data/wiki/inc/init.php:239) in /data/wiki/inc/auth.php on line 430

Warning: Cannot modify header information - headers already sent by (output started at /data/wiki/inc/init.php:239) in /data/wiki/inc/Action/Export.php on line 103

Warning: Cannot modify header information - headers already sent by (output started at /data/wiki/inc/init.php:239) in /data/wiki/inc/Action/Export.php on line 103

Warning: Cannot modify header information - headers already sent by (output started at /data/wiki/inc/init.php:239) in /data/wiki/inc/Action/Export.php on line 103
C D E(注意一下一条链的话，树根不一定就是1了) F 辣鸡模拟题，写吐了。 G 很常见的一种思路，先构造出最小的，每次变得最大的就是第i个和第n-i+1个交换，如果发现大了的话，显然可以在剩下的找到和多出来的相等的。