题目链接:http://codeforces.com/contest/814/problem/D 题意:给出奇数个舞者,每个舞者都有中心坐标和行动半径,而且这些点组成的园要么相互包含要么没有交集求,讲这些点分成两部分最大面积是多少. 面积计算方法详见题目,很好理解有图示. 题解:这题挺简单的就考虑一下包含与不包含的就行了.具体看一下代码挺好理解的,主要是题目给出的这些点组成的园要么相互包含要么没有交集求导致 这题变得很简单 #include <iostream> #include <cm…

Codeforces Round #418 (Div. 2) D. An overnight dance in discotheque 题意: 给\(n(n <= 1000)\)个圆,圆与圆之间不存在相交关系,只存在包含与不包含关系,现在问你把这一堆圆分成两组,求每组圆的异或并和的最大值. 思路:最简单的做法是贪心的做法,算出每个圆被包含的次数,为偶数则贡献为正,奇数为贡献为负. 现在主要学习一下树形dp的做法 由于圆不存在相交的情况,所以可以把所有的圆建成树,即把每棵树上的点分成两组,分别建成…

An overnight dance in discotheque time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output The crowdedness of the discotheque would never stop our friends from having fun, but a bit more spaciousne…

The crowdedness of the discotheque would never stop our friends from having fun, but a bit more spaciousness won't hurt, will it? The discotheque can be seen as an infinite xy-plane, in which there are a total of n dancers. Once someone starts moving…

题目链接 正解:贪心. 首先我们可以计算出每个圆被多少个圆覆盖. 很显然,最外面的圆是肯定要加上的. 然后第二层的圆也是要加上的.那么第三层就不可能被加上了.同理,第四层的圆又一定会被加上. 然后我们可以发现一个贪心策略,没被覆盖和被覆盖奇数次的圆加上,被覆盖偶数次的圆减去. 可以发现这样的贪心策略是最优的. #include <bits/stdc++.h> #define il inline #define RG register #define ll long long #define N…

大意: 给定n个不相交的圆, 求将n个圆划分成两部分, 使得阴影部分面积最大. 贪心, 考虑每个连通块, 最外层大圆分成一部分, 剩余分成一部分一定最优. #include <iostream> #include <iostream> #include <algorithm> #include <cstdio> #include <math.h> #include <set> #include <map> #include…

一道树形dp裸体,自惭形秽没有想到 首先由于两两圆不能相交(可以相切)就决定了一个圆和外面一个圆的包含关系 又可以发现这样的树中,奇数深度的圆+S,偶数深度的圆-S 就可以用树形dp 我又写挫了= = #include<cmath> #include<map> #include<iostream> #include<cstring> #include<cstdio> #include<set> #include<vector&g…

//yy:因为这题多组数据,DP预处理存储状态比每次尺取快多了,但是我更喜欢这个尺取的思想. 题目链接:codeforces 814 C. An impassioned circulation of affection 题意:给出字符串长度n (1 ≤ n ≤ 1 500),字符串s由小写字母组成,q个询问q (1 ≤ q ≤ 200 000),每个询问为:mi (1 ≤ mi ≤ n)   ci ,表示可以把任意mi个字母改成ci,求每次改变后只由ci组成的最长连续字串的长度. 解法一:尺取法…

题目链接: Codeforces 669D Little Artem and Dance 题目描述: 给一个从1到n的连续序列,有两种操作: 1:序列整体向后移动x个位置, 2:序列中相邻的奇偶位置互换. 问:q次操作后,输出改变后的序列? 解题思路: 刚开始只看了第一组样例,发现相邻的奇偶位一直在一起,于是乎就开始writing code,写完后发现并不是正解!!!!就去推了一下第三个样例,总是这组实例通过,那组实例卡死,,,,,,,最后终于成功的Mengbility.今天突然想起来,其实整体…

题目链接:http://codeforces.com/contest/814/problem/C 题意:给出一串字符串然后q个询问,问替换掉将m个字符替换为字符c,能得到的最长的连续的字符c是多长 题解:预处理dp[i][j]表示第i种字幕添加j个最长的连续为多长.然后与处理一下sum[j]表示前j个里有几个不是第i种字母的. 然后for一遍二分一下.更新dp. #include <iostream> #include <cstring> #include <vector&g…

http://codeforces.com/problemset/problem/669/D 题意:n个数1~N围成一个圈.q个操作包括操作1:输入x, 所有数右移x.操作2:1,2位置上的数(swap(a[1], a[2])交换:3,4交换.... 题解:观察,发现所有奇数行为都是一样的,偶数同理,(对于操作1 两者相同,对于操作2 奇数位++,偶数位上--: 模拟1,2,即可,然后依次输出其它数字即可.(看清 ac代码: #define _CRT_SECURE_NO_WARNINGS #in…

B. Little Artem and Dance time limit per test 2 second memory limit per test 256 megabytes input standard input output standard output Little Artem is fond of dancing. Most of all dances Artem likes rueda - Cuban dance that is danced by pairs of boys…

模拟. 每个奇数走的步长都是一样的,每个偶数走的步长也是一样的. 记$num1$表示奇数走的步数,$num2$表示偶数走的步数.每次操作更新一下$num1$,$num2$.最后输出. #pragma comment(linker, "/STACK:1024000000,1024000000") #include<cstdio> #include<cstring> #include<cmath> #include<algorithm> #i…

http://codeforces.com/problemset/problem/733/C 题意:给出一个序列的怪兽体积 ai,怪兽只能吃相邻的怪兽,并且只有体积严格大于相邻的怪兽才能吃,吃完之后,这只怪兽的体积会变成原体积 + 吃的怪兽的体积,接下来给出 k 个怪兽的体积 bi,问能不能满足经过一系列操作后让剩下的怪兽体积变得满足下面的序列. 思路:昨晚想的时候觉得好复杂,今天补题发现实际上只有一种情况,就是每一个区间里的怪兽体积对应于一个 bi,然后拆成 k 个区间,分别找区间里面最大的去…

题目链接:http://codeforces.com/contest/706/problem/D 题意很简单不多说. 把一个数当作二进制插入字典树中,按照xor的性质,1找0,0找1,贪心即可. 注意的是一开始集合中就有0,所以一开始'?'查询时输出他本身. //#pragma comment(linker, "/STACK:102400000, 102400000") #include <algorithm> #include <iostream> #incl…

D. Fish Weight 题目连接: http://www.codeforces.com/contest/298/problem/D Description It is known that there are k fish species in the polar ocean, numbered from 1 to k. They are sorted by non-decreasing order of their weight, which is a positive number.…

A. Snow Footprints 题目连接: http://www.codeforces.com/contest/298/problem/A Description There is a straight snowy road, divided into n blocks. The blocks are numbered from 1 to n from left to right. If one moves from the i-th block to the (i + 1)-th blo…

C. Alternative Thinking Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/604/problem/C Description Kevin has just recevied his disappointing results on the USA Identification of Cows Olympiad (USAICO) in the form of a binary…

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…

A. Bits Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/484/problem/A Description Let's denote as the number of bits set ('1' bits) in the binary representation of the non-negative integer x. You are given multiple queries…

D. Phillip and Trains Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/586/problem/D Description The mobile application store has a new game called "Subway Roller". The protagonist of the game Philip is located in one en…

http://codeforces.com/contest/469/problem/D 题目大意: 给你一个长度为n数组,给你两个集合A.B,再给你两个数字a和b.A集合中的每一个数字x都也能在a集合中找到x-a的数字.同理,b集合也一样.问,这个数组能否分成这两个集合?(然后坑点就是集合里面的元素可以为空) 思路一: 首先定义type函数,-1表示不在任何集合内,0表示A集合内,1表示B集合,2表示该元素是a的一半.(之所以要表示成2的原因是因为这个数值很特殊,a-x=x,所以他可以满足A集合…

题目: 题目原文链接:http://codeforces.com/contest/845/problem/C 题意:现在我们有一个电视清单,有两个电视,电视清单上有每一个节目的开始时间和结束时间. 电视不能接连不间断的播放,例如TV1播放完1-2点的节目后不能接着播放2-3点的电视,除非在TV2上播放,如果TV2也正在播放则不能播放完清单. 思路: 1.对清单排序,让开始时间早的靠前,如果开始时间相同,结束时间早的靠前. 2.如果TV1已经结束.就把这一个节目的结束时间赋给TV1,然后看下一个节…

https://codeforces.com/contest/1140/problem/C 题意 每首歌有\(t_i\)和\(b_i\)两个值,最多挑选m首歌,使得sum(\(t_i\))*min(\(b_i\))最大 题解 假如最小的\(b_i\)确定了,那么拿得越多越好 枚举最小的\(b_i\)然后取剩下最大的\(t_i\) 两种做法 1.从\(b_i\)大向小扫,这样用优先队列维护最大的那些\(t_i\)(丢弃最小的) 2.用两个优先队列模拟 代码 //做法1 #include<bits/…

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, so…

B. Sort the Array 题目连接: http://codeforces.com/contest/451/problem/B Description Being a programmer, you like arrays a lot. For your birthday, your friends have given you an array a consisting of n distinct integers. Unfortunately, the size of a is to…

B. Mike and Shortcuts 题目连接: http://www.codeforces.com/contest/689/problem/B Description Recently, Mike was very busy with studying for exams and contests. Now he is going to chill a bit by doing some sight seeing in the city. City consists of n inter…

D. Theseus and labyrinth 题目连接: http://www.codeforces.com/contest/676/problem/D Description Theseus has just arrived to Crete to fight Minotaur. He found a labyrinth that has a form of a rectangular field of size n × m and consists of blocks of size 1…

B. Computer Game 题目连接: http://www.codeforces.com/contest/37/problem/B Description Vasya's elder brother Petya loves playing computer games. In one of his favourite computer games Petya reached the final level where a fight with the boss take place. W…

题目链接: http://codeforces.com/contest/606/problem/D D. Lazy Student time limit per test2 secondsmemory limit per test256 megabytes 问题描述 Student Vladislav came to his programming exam completely unprepared as usual. He got a question about some strange…