B2. Character Swap (Hard Version) This problem is different from the easy version. In this version Ujan makes at most 2…

This problem is different from the easy version. In this version Ujan makes at most 2n2n swaps. In addition, k≤1000,n≤50k≤1000,n≤50 and it is necessary to print swaps themselves. You can hack this problem if you solve it. But you can hack the previou…

B1. Character Swap (Easy Version) This problem is different from the hard version. In this version Ujan makes exactly one exchange. You can hack this problem only if you solve both problems. After struggling and failing many times, Ujan decided to tr…

This problem is different from the hard version. In this version Ujan makes exactly one exchange. You can hack this problem only if you solve both problems. After struggling and failing many times, Ujan decided to try to clean up his house again. He…

链接: https://codeforces.com/contest/1234/problem/B2 题意: The only difference between easy and hard versions are constraints on n and k. You are messaging in one of the popular social networks via your smartphone. Your smartphone can show at most k most…

题意:给你两个长度为\(n\)的01串\(s\)和\(t\),可以选择\(s\)的前几位,取反然后反转,保证\(s\)总能通过不超过\(2n\)的操作得到\(t\),输出变换总数,和每次变换的位置. 题解:我们现将\(s\)串全部变成\(1\)或\(0\),确保\(s[n]=t[n]\),然后我们倒着遍历\(t\),若遇到相邻的两个字符不同,我们就对\(s\)中相应的位置执行一次操作,然后继续遍历,如下图: 代码: int t; int n; char s[N],tmp[N]; vector<i…

题意:给你两个长度为\(n\)的01串\(s\)和\(t\),可以选择\(s\)的前几位,取反然后反转,保证\(s\)总能通过不超过\(3n\)的操作得到\(t\),输出变换总数,和每次变换的位置. 题解:构造题一定要充分利用题目所给的条件,对于\(s\)中的某一位i,假如它和\(t\)中的对应位置不同,我们先对前i个字符取反反转,然后再对第一个字符取反反转(就选了一个,反不反都无所谓),在取前i个位置取反反转,这样,我们就将第i个位置变换了,消耗了3次操作.这样就一定能保证在\(3n\)之内完…

久违的写篇博客吧 A. Maximum Square 题目链接:https://codeforces.com/contest/1243/problem/A 题意: 给定n个栅栏,对这n个栅栏进行任意排序,问可形成的最大正方形面积是多少 分析: 水题. 先排个序 , 然后暴力枚举正方形边长就可以了 #include<bits/stdc++.h> #define ios std::ios::sync_with_stdio(false) #define sd(n) scanf("%d&qu…

Codeforces Round #599 (Div. 2) D. 0-1 MST Description Ujan has a lot of useless stuff in his drawers, a considerable part of which are his math notebooks: it is time to sort them out. This time he found an old dusty graph theory notebook with a descr…

难题不会啊…… 我感觉写这个的原因就是因为……无聊要给大家翻译题面 A. Maximum Square 简单题意: 有$n$条长为$a_i$,宽为1的木板,现在你可以随便抽几个拼在一起,然后你要从这一大块木板中裁出一块最大的正方形. $1 \leq a_i \leq n \leq 1000$ 多测,$T \leq 10$ 给个官网的图: 直接排序然后扫就行了,这数据范围是不是让你想什么神奇东西了? #include <algorithm> #include <iostream> #…

原题 https://codeforces.com/contest/1249/problem/B2 这道题一开始给的数组相当于地图的路标,我们只需对每个没走过的点进行dfs即可 #include <bits/stdc++.h> using namespace std;const int maxn=2e5+20;int a[maxn],b[maxn],c[maxn];int dfs(int pos,int step){//传递坐标与步数 if(b[pos]==1){//再次遇到b[pos],返回…

链接: http://codeforces.com/contest/1243/problem/B2 题目大意: 两个字符串,判断能否通过交换为从而使得这两个字符串完全一致,如不可以的话,直接输出NO,可以的话输出YES,并且输出每一步的交换位置. 思路:如果没个字符出现的次数为偶数次的话,那么一定可以成功,否则的话一定是NO. 如果说S[i]!=T[i],假如说,S中有与T[i]相同的元素,那么直接交换就可以了,操作次数为1,在T中找S[i]操作相同. S中没有与T[i]相同的元素,我们保证了每…

排序+暴力 #include<bits/stdc++.h> using namespace std; #define int long long #define N 1005000 int arr[N]; signed main(){ int _,n; cin>>_; while(_--){ cin>>n; ;i<=n;i++) cin>>arr[i]; sort(arr+,arr++n); ; ;i<=n;i++){ ; ; ;j--){ if…

题:https://codeforces.com/contest/1243/problem/D 分析:找全部可以用边权为0的点连起来的全部块 然后这些块之间相连肯定得通过边权为1的边进行连接 所以答案就是这些块的总数-1: #include<bits/stdc++.h> using namespace std; typedef long long ll; #define pb push_back ; set<int>s,g[M]; int vis[M]; void bfs(int…

这题写起来真的有点麻烦,按照官方题解的写法 先建图,然后求强连通分量,然后判断掉不符合条件的换 最后做dp转移即可 虽然看起来复杂度很高,但是n只有15,所以问题不大 #include <iostream> #include <fstream> #include <vector> #include <set> #include <map> #include <bitset> #include <algorithm> #in…

C. Sum Balance Ujan has a lot of numbers in his boxes. He likes order and balance, so he decided to reorder the numbers. There are…

D. 0-1 MST Ujan has a lot of useless stuff in his drawers, a considerable part of which are his math notebooks: it is time to sort them out. This time he found an old dusty graph theory notebook with a description of a graph. It is an undirected weig…

C. Tile Painting Ujan has been lazy lately, but now has decided to bring his yard to good shape. First, he decided to paint the path from his house to the gate. The path consists of…

A. Maximum Square Ujan decided to make a new wooden roof for the house. He has…

Ujan has been lazy lately, but now has decided to bring his yard to good shape. First, he decided to paint the path from his house to the gate. The path consists of nn consecutive tiles, numbered from 11 to nn. Ujan will paint each tile in some color…

Ujan decided to make a new wooden roof for the house. He has nn rectangular planks numbered from 11 to nn. The ii-th plank has size ai×1ai×1 (that is, the width is 11 and the height is aiai). Now, Ujan wants to make a square roof. He will first choos…

题意:就是给你一个n,然后如果  n mod | i - j | == 0  并且 | i - j |>1 的话,那么i 和 j 就是同一种颜色,问你最大有多少种颜色? 思路: 比赛的时候,看到直接手推,发现有点东西,直接打表找出了规律 —— 如果 n的质因子只有一个,那么总数就是 那个 质因子.其它都为 1. 今天上课的时候无聊,还是试着推了一下原理. 1.如果一个数只有一个质因子 x ,那么  n-x .n-2x.n-3x ……等等全为一种颜色,也就是说每隔 x个就是同种颜色,这样的话就是有…

F. Restore a Number   Vasya decided to pass a very large integer n to Kate. First, he wrote that number as a string, then he appended to the right integer k — the number of digits in n. Magically, all the numbers were shuffled in arbitrary order whil…

https://codeforces.com/contest/1118/problem/F1 #include<bits/stdc++.h> using namespace std; int n; vector<int> color; vector<vector<int> > tree; ,blue=; ; pair<){ ); ); ;i<tree[v].size();i++){ int u=tree[v][i]; if(u!=p){//避免回…

A. Drazil and Factorial 题目连接: http://codeforces.com/contest/516/problem/A Description Drazil is playing a math game with Varda. Let's define for positive integer x as a product of factorials of its digits. For example, . First, they choose a decimal…

B. Fox and Minimal path 题目连接: http://codeforces.com/contest/388/problem/B Description Fox Ciel wants to write a task for a programming contest. The task is: "You are given a simple undirected graph with n vertexes. Each its edge has unit length. You…

E. Berland Local Positioning System Time Limit: 1 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/534/problem/E Description In Berland a bus travels along the main street of the capital. The street begins from the main square and looks l…

任意门:http://codeforces.com/contest/1118/problem/F1 F1. Tree Cutting (Easy Version) time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You are given an undirected tree of nn vertices. Some vert…

传送门:http://codeforces.com/contest/1092/problem/D2 D2. Great Vova Wall (Version 2) time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Vova's family is building the Great Vova Wall (named by Vo…

传送门:http://codeforces.com/contest/1092/problem/D1 D1. Great Vova Wall (Version 1) time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Vova's family is building the Great Vova Wall (named by Vo…