鸽着,我不知道为什么对? 题意: 思路: code: #include<bits/stdc++.h> using namespace std; const int N=5e5+5; int p[N],nxt[N],to[N],head[N],ecnt,d[N]; void add_edge(int u,int v,int i) {nxt[++ecnt]=head[u];d[ecnt]=i;to[ecnt]=v;head[u]=ecnt;} int fa[N],dep[N],In[N],id[N…

C. LIS or Reverse LIS? D. Circular Spanning Tree E. Unordered Swaps F MCMF?…

https://www.hackerrank.com/challenges/minimum-swaps-2/problem Minimum Swaps II You are given an unordered array consisting of consecutive integers  [1, 2, 3, ..., n] without any duplicates. You are allowed to swap any two elements. You need to find t…

自从c++11起,bitset用于unordered container,将会提供默认的hash函数. 在gcc中,相关代码如下: // DR 1182. /// std::hash specialization for bitset. template<size_t _Nb> struct hash<_GLIBCXX_STD_D::bitset<_Nb>> : public std::unary_function<_GLIBCXX_STD_D::bitset&l…

Serializable unordered set 可序列化哈希set #include <boost/algorithm/string/predicate.hpp> #include <boost/exception/diagnostic_information.hpp> #include <boost/exception_ptr.hpp> #include <boost/archive/text_oarchive.hpp> #include <b…

1.散列容器(hash container)  散列容器通常比二叉树的存储方式可以提供更高的访问效率. #include <boost/unordered_set.hpp> #include <boost/unordered_map.hpp> using namespace boost; 2.散列集合简介 unordered库提供两个散列集合类unordered_set和unordered_multiset,STLport也提供hash_set和hash_multiset,它们的接…

[codeforces 339]E. Three Swaps 试题描述 Xenia the horse breeder has n (n > 1) horses that stand in a row. Each horse has its own unique number. Initially, the i-th left horse has number i. That is, the sequence of numbers of horses in a row looks as foll…

Mapping the Swaps Sorting an array can be done by swapping certain pairs of adjacent entries in the array. This is the fundamental technique used in the well-known bubble sort. If we list the identities of the pairs to be swapped, in the sequence the…

题目例如以下: Mapping the Swaps  Sorting an array can be done by swapping certain pairs of adjacent entriesin the array. This is the fundamental technique used in the well-knownbubble sort. If we list the identities of the pairs to be swapped, in thesequen…

E. Three Swaps time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Xenia the horse breeder has n (n > 1) horses that stand in a row. Each horse has its own unique number. Initially, the i-th le…