后续: 点分治标程 使用father数组 比使用vis数组优秀(不需要对vis初始化) https://codeforces.com/problemset/problem/1174/F https://codeforces.com/blog/entry/67388 有助于理解树链剖分 和 点分治 题解写得挺好 重链 重链中的点的子树的大小是最大的 重链外的点作为根节点的 子树 大小 < 1/2总的点数目 每次处理后到达重链外的点(若是重链内的点,判断结束) #include <cstdio&g…

F. Ehab and a weird weight formula 题目链接:https://codeforces.com/contest/1088/problem/F 题意: 给出一颗点有权值的树,满足只有一个点的权值最小,然后除开这个点,每个点都有一个权值比它更小的点与之相邻. 然后要求你重构这颗树,满足点权及边权和最小. 点权计算方法: au = au*num(num为与之相邻边的个数); 边权计算方法: e{u,v},we = dis(u,v)*min(au,av)  (dis(u,v…

https://codeforces.com/contest/1174/problem/E dp 好题 *(if 满足条件) 满足条件 *1 不满足条件 *0 ///这代码虽然写着方便,但是常数有点大 #include <cstdio> #include <cstdlib> #include <cmath> #include <cstring> #include <string> #include <algorithm> #inclu…

链接:https://codeforces.com/contest/1174/problem/C 题意: You're given an integer nn. For every integer ii from 22 to nn, assign a positive integer aiai such that the following conditions hold: For any pair of integers (i,j)(i,j), if ii and jj are coprime…

链接:https://codeforces.com/contest/1174/problem/B 题意: You're given an array aa of length nn. You can perform the following operation on it as many times as you want: Pick two integers ii and jj (1≤i,j≤n)(1≤i,j≤n) such that ai+ajai+aj is odd, then swap…

链接:https://codeforces.com/contest/1174/problem/A 题意: You're given an array aa of length 2n2n. Is it possible to reorder it in such way so that the sum of the first nn elements isn't equal to the sum of the last nn elements? 思路: 排序后求前一半和后一半的和比较. 代码: #…

Codeforces Round #563 (Div. 2)/CF1174 CF1174A Ehab Fails to Be Thanos 其实就是要\(\sum\limits_{i=1}^n a_i\)与\(\sum\limits_{n+1}^{2n}a_i\)差值最大,排一下序就好了 CF1174B Ehab Is an Odd Person 一个显然的结论就是如果至少有一个奇数和一个偶数,那么是可以随意调整的,也就是升序排序 否则不可以进行任何操作 code CF1174C Ehab an…

Codeforces Round #485 (Div. 2) F. AND Graph 题目连接: http://codeforces.com/contest/987/problem/F Description You are given a set of size $m$ with integer elements between $0$ and $2^{n}-1$ inclusive. Let's build an undirected graph on these integers in…

Codeforces Round #486 (Div. 3) F. Rain and Umbrellas 题目连接: http://codeforces.com/group/T0ITBvoeEx/contest/988/problem/E Description Polycarp lives on a coordinate line at the point x=0. He goes to his friend that lives at the point x=a. Polycarp can…

题目链接 Codeforces Round #501 (Div. 3) F. Bracket Substring 题解 官方题解 http://codeforces.com/blog/entry/60949 ....看不懂 设dp[i][j][l]表示前i位,左括号-右括号=j,匹配到l了 状态转移,枚举下一个要填的括号,用next数组求状态的l,分别转移 代码 #include<bits/stdc++.h> using namespace std; const int maxn = 207;…