Coldfresh的博客

Giant chess is quite common in Geraldion. We will not delve into the rules of the game, we’ll just say that the game takes place on an h × w field, and it is painted in two colors, but not like in ches

Little Mishka enjoys programming. Since her birthday has just passed, her friends decided to present her with array of non-negative integers a1, a2, …, an of n elements!Mishka loved the array and she i

题目链接 题目大意，在一串无穷的1，2，3…n的串值，有k次操作，每次操作给出两个数a，b，即把坐标a和坐标b的值交换，问最后有多少个逆序对，0<=k<=105,a和b在int范围内0<=k<=10^5,a和b在int范围内 分析：问题的关键是，操作次数相对与整个序列是比较稀疏的，也就是说会有许多连续的数串 ，我们就是把这些连续的数串缩微一个点，而点的权值即为这个数串的数量，用离散化来处理，最后

Leha somehow found an array consisting of n integers. Looking at it, he came up with a task. Two players play the game on the array. Players move one by one. The first player can choose for his move a

Mahmoud wrote a message s of length n. He wants to send it as a birthday present to his friend Moaz who likes strings. He wrote it on a magical paper but he was surprised because some characters disapp

A group of n cities is connected by a network of roads. There is an undirected road between every pair of cities, so there are roads in total. It takes exactly y seconds to traverse any single road. ...

Vitya is studying in the third grade. During the last math lesson all the pupils wrote on arithmetic quiz. Vitya is a clever boy, so he managed to finish all the tasks pretty fast and Oksana Fillipovn...

Connected undirected weighted graph without self-loops and multiple edges is given. Graph contains n vertices and m edges. For each edge (u, v) find the minimal possible weight of the spanning tree t...

做法： 我之前错误的做法是从前往后推的，优先最小，但是显然这是错误的，随便构造一个就能找到反例，当时没什么时间了，就没有怎么仔细想。因为实际上当越往根节点靠近时，这个点值应该越大越好，因为他可以以他为根子树的贡献越多，使得总体所有点权和越小，这个从直觉上就可以分析出来应该是没有问题，所以这个应该得从后往前推，如果这个点的s值没确定，那么应该取他的子节点的的s值当中的最小值。如果发现他的子节点都...