大树的难题！？？
题目链接：http://202.118.67.200:7217/codesheaven/problem.php?id=1046
参考题解：http://dutacm.club:7217/codesheaven/blog/2017/01/04/dut-star-weekly-contest-3-problem-f-solution/
wait for solving...
题目链接：http://202.118.67.200:7217/codesheaven/problem.php?id=1046
参考题解：http://dutacm.club:7217/codesheaven/blog/2017/01/04/dut-star-weekly-contest-3-problem-f-solution/
wait for solving...