题目戳这里. 首先题解给的是并查集的做法.这个做法很好想,但是很难码.用线段树数来维护并查集,暴力合并. 这里推荐另一个做法,可以无视\(K\)的限制.我们给每条边加个边权,这个边权为这条边左端点的值.然后我们将询问离线,按\(r\),从小到大处理. 对于当前询问\([l,r]\)我们用lct维护所有右端点\(\le r\)的边构成的最大生成树,然后用树状数组查询生成树中边权\(\ge l\)的边有几条即可. #include<algorithm> #include<iostream&g…

Content 有一个序列 \(a_1,a_2,a_3,...,a_n\),对于 \(i\in[1,n]\),只要 \(i\leqslant n-i+1\),就把闭区间 \([i,n-i+1]\) 内的所有数翻转.现在给定你翻转后的序列,求原来的序列. 数据范围:\(1\leqslant n\leqslant 2\times 10^5,-10^9\leqslant a_i\leqslant 10^9\). Solution 做这题之前,我们来看这个序列的规律: 首先拿出一个序列 \([2,6,8…

D. Animals and Puzzle 题目连接: http://codeforces.com/contest/713/problem/D Description Owl Sonya gave a huge lake puzzle of size n × m to hedgehog Filya as a birthday present. Friends immediately started to assemble the puzzle, but some parts of it turn…

[题目]D. Animals and Puzzle [题意]给定n*m的01矩阵,Q次询问某个子矩阵内的最大正方形全1子矩阵边长.n,m<=1000,Q<=10^6. [算法]动态规划DP+二维ST表 [题解]设f[i][j]为以(i,j)为右下角的最大正方形全1子矩阵. f[i][j]=min{ f[i-1][j-1] , f[i][j-1] , f[i-1][j] }+1 然后用二维ST表处理f[i][j]的子矩阵最小值. 对于每次询问,二分边长x,答案即子矩阵(x1+x-1,y1+x-1…

题目描述 Of course our child likes walking in a zoo. The zoo has n areas, that are numbered from 1 to n. The i-th area contains ai animals in it. Also there are m roads in the zoo, and each road connects two distinct areas. Naturally the zoo is connected…

C. Timofey and a tree time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Each New Year Timofey and his friends cut down a tree of n vertices and bring it home. After that they paint all the n…

A. Sea Battle time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output In order to make the "Sea Battle" game more interesting, Boris decided to add a new ship type to it. The ship consists of…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output Young Timofey has a birthday today! He got kit of n cubes as a birthday present from his parents. Every cube has a number ai, which is written on…

time limit per test2 seconds memory limit per test256 megabytes inputstandard input outputstandard output Each New Year Timofey and his friends cut down a tree of n vertices and bring it home. After that they paint all the n its vertices, so that the…

Each New Year Timofey and his friends cut down a tree of n vertices and bring it home. After that they paint all the n its vertices, so that the i-th vertex gets color ci. Now it's time for Timofey birthday, and his mother asked him to remove the tre…