S_G_G的博客

【题目链接】http://www.lydsy.com/JudgeOnline/status.php?user_id=SGG 【解题思路】暴力枚举中点，直接计数即可 【呆马】#include<cstdio>#include<algorithm>#include<cmath>#include<cstdlib>#include<iostream>#define ll long longco

【题目链接】http://www.lydsy.com/JudgeOnline/problem.php?id=1060 【呆马】#include<cstdio>#include<algorithm>#include<cmath>#include<cstdlib>#include<iostream>#define ll long longconst int N=500001;using

【题目链接】http://www.lydsy.com/JudgeOnline/problem.php?id=1562 【解题思路】%byvoid https://www.byvoid.com/blog/noi-2009-transform/ 【呆马（贪心+dfs）】#include<cstdio>#include<algorithm>#include<cmath>#include<cstd

【题目大意】给一棵n(【解题思路】先将相同颜色的连通块缩点，然后我们就得到了一棵黑白相间的树。我们可以发现当确定一个点为根时的最少操作数为树的高度减一。当以树的直径的中点为根时树的高度最小。因此答案为(树的直径长度+1)/2。用dp或者两次dfs求出树的直径。【呆马】#include#include#inclu