Building Forest CodeForces - 195E 这题意真是难懂啊...话说"An oriented weighted forest is an acyclic weighted digraph in which from each vertex at most one edge goes."这句话到底什么意思... 题意:有n个点要按照1-n的顺序依次插入一个带边权的森林(森林一开始没有任何点.边),第i+1行描述第i个点插入后的操作.如果某一行为(k,  v1, …

A. Let's Watch Football 记时间为\(t\), 则\(bt+(b-a)c>=0\),可得\[t \ge \frac{c(a-b)}{b}\] B. After Training 优先队列维护下即可,也可找规律然后\(O(n)\)扫一遍即可. C. Try and Catch 字符串模拟. 去除首尾空格 str.erase(0, str.find_first_not_of(' ')); str.erase(str.find_last_not_of(' ') + 1); D.…

Building Permutation CodeForces - 285C Permutation p is an ordered set of integers p1,  p2,  ...,  pn, consisting of n distinct positive integers, each of them doesn't exceed n. We'll denote the i-th element of permutation p as pi. We'll call number …

CF1039D You Are Given a Tree 容易发现,当 \(k\) 不断增大时,答案不断减小,且 \(k\) 的答案不超过 \(\lfloor\frac {n}{k}\rfloor\) ,因此不同的答案个数是 \(\sqrt n\) 级别的,可以用一种类似整体二分的方式求解. 对于一个 \(k\) ,从叶子节点贪心向上匹配即可得到答案. 点击查看代码 #include<bits/stdc++.h> using namespace std; int n; int ver[2000…

B. Biridian Forest Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/329/problem/B Description You're a mikemon breeder currently in the middle of your journey to become a mikemon master. Your current obstacle is go through t…

D. Biridian Forest time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You're a mikemon breeder currently in the middle of your journey to become a mikemon master. Your current obstacle is go…

题目传送门 /* 题意:给出无向无环图,每一个点的度数和相邻点的异或和(a^b^c^....) 图论/位运算:其实这题很简单.类似拓扑排序,先把度数为1的先入对,每一次少一个度数 关键在于更新异或和,精髓:a ^ b = c -> a ^ c = b, b ^ c = a; */ #include <cstdio> #include <cstring> #include <cmath> #include <algorithm> #include <…

题目传送门 /* 题意:给出无向无环图,每一个点的度数和相邻点的异或和(a^b^c^....) 图论/位运算:其实这题很简单.类似拓扑排序,先把度数为1的先入对,每一次少一个度数 关键在于更新异或和,精髓:a ^ b = c -> a ^ c = b, b ^ c = a; */ #include <cstdio> #include <cstring> #include <cmath> #include <algorithm> #include <…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output PolandBall lives in a forest with his family. There are some trees in the forest. Trees are undirected acyclic graphs with k vertices and k - 1 e…

题目链接:http://codeforces.com/problemset/problem/501/C 题目意思:有 n 个点,编号为 0 - n-1.给出 n 个点的度数(即有多少个点跟它有边相连)以及跟它相连的点的编号的异或结果.最后需要输出整幅图的所有边的情况. 这道题确实是一道很好的题目!!!!它说拓扑排序的变形,需要队列的运用,还有就是异或计算的性质!!!(非一般厉害) 由于是无向无环的简单图,换言之就是一棵树啦^_^.那么它就肯定有叶子结点,叶子节点的度数为1,此时它相邻点的异或结果…