AtCoder Beginner Contest 163 题目链接D: 看样例+分析得知,假设现在要选ii个,那么能达到的最大的值就是sumi1=∑nx=n−i+1xsumi1=∑x=n−i+1nx, 最小值就是sumi2=∑i−1x=0xsumi2=∑x=0i−1x,那么每次可选择的数量就是sum1−sum2+1sum1−sum2+1,那么答案就为∑n+1i=k(sumi1...
AtCoder Beginner Contest 163 传送门 A - Circle Pond A.cpp B - Homework B.cpp C - management 题意:给一棵N个节点的有根树,求每个节点的儿子数。 数据范围:2≤N≤2×1052≤N≤2×105 题解:由于输入直接给的是每个节点的父节点,直接计数即可。 C.cpp D - Sum of Large Numbers 题意:当前有N ...
AtCoder Beginner Contest 163(D,E(区间dp),F(树上路径问题)),题目链接今天的题都很不错D-SumofLargeNumbers题意:求至少选k个数和的种类数。做法:刚开始感觉很难,涉及大数和、方案数。考虑k=2由于n+1个数是连续的,那我选最小的k个数求和:mi和最大的k个数求和:mx
AtCoder Beginner Contest 163E - Active Infants(DP) Problem Statement There are NN children standing in a line from left to right. The activeness of the ii-th child from the left is AiAi. You can rearrange these children just one time in any order you like. When a child who originally ...
# Preface 补题,这场比赛的时候被拉去开科研组会了,所以就没现场打了 这两天军训在伤病连划水,白天可以好好想题目舒服的一批 这场D题确实很妙,需要一些竞赛图相关的知识才能想到转化,不过也算是学到一个重要trick了吧 # **A - Divide String** 显然只要考虑能否分成两
但是n=12,420n=12,420时1t(t+1)21t(t+1)2还可以跟前面的继续合并,因此要特判。 code // Problem: C - Harmonic Mean // Contest: AtCoder - AtCoder Regular Contest 163 // URL: https://atcoder.jp/contests/arc163/tasks/arc163_c ...
代码 题目: 思路:因为这里的数是连续的,所以 从n个数中选k个数出来的种类数 = k个最大的数 - k个最小的数 + 1 因为是做差,所以直接可以忽略那个10^100, 计算和的时候,因为是连续的,所以利用等差数列求和公式 列如样例1 最大的两个数-最小的两个数+1 = 5,选两个数时,所以有5种 ...
Atcoder beginner contest 163 f path pass i 传送门:https://atcoder.jp/contests/abc163/tasks/abc163_f 题目大意:一颗n个节点的树,每个节点有一个颜色。求对每一个颜色,至少经过一个该颜色节点的简单路径数量。 分析:虽然有O(n)的做法,但是这里还是贴一下虚树的做法。虚树的做法大概是:对每一种颜色建立...
[AtCoder Beginner Contest 163]F - path pass i(树型dfs,容斥定律) 链接:https://atcoder.jp/contests/abc163/tasks/abc163_f Problem Statement We have a tree with NN vertices numbered 11 to NN. The ii-th edge in this tree connects Vertex aiai and bibi. Additionally, each vertex is painted...
AtCoder Beginner Contest 163E - Active Infants(DP) Problem Statement There are NN children standing in a line from left to right. The activeness of the ii-th child from the left is AiAi. You can rearrange these children just one time in any order you like. ...