无脑暴力题,算出所有点到圆心p1的距离的平方,从小到大排序. 然后暴力枚举p1的半径的平方,计算剩余点中到p2的最大距离的平方,枚举过程中记录答案 #include<cstdio> #include<cstring> #include<vector> #include<cmath> #include<queue> #include<list> #include<algorithm> using namespace std;…

C. Watering Flowers 题目连接: http://www.codeforces.com/contest/617/problem/C Descriptionww.co A flowerbed has many flowers and two fountains. You can adjust the water pressure and set any values r1(r1 ≥ 0) and r2(r2 ≥ 0), giving the distances at which t…

题意与分析 (CodeForces 617C) 题意是这样的:一个花圃中有若干花和两个喷泉,你可以调节水的压力使得两个喷泉各自分别以\(r_1\)和\(r_2\)为最远距离向外喷水.你需要调整\(r_1,r_2\)的值使得所有的花都能被水所灌溉--换句话说,每一朵花要么到第一个喷泉的距离不超过\(r_1\),要么到第二个喷泉的距离不超过\(r_2\).当然如果两个条件都满足也是可以的.你需要用尽可能少的水来实现以上要求,也就是说使得\(r_1^2+r_2^2\)尽可能的小.找出这个最小值. 那么…

C. Watering Flowers time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output A flowerbed has many flowers and two fountains. You can adjust the water pressure and set any values r1(r1 ≥ 0) and r2(r…

题目: http://www.codeforces.com/contest/617/problem/C 自己感觉是挺有新意的一个题目, 乍一看挺难得(= =). 其实比较容易想到的一个笨办法就是:分别计算出每个点到喷泉的距离,然后分别按照距离远近排序(要用到两个数组),然后选定一个喷泉,从近到远依次选点,然后标记该点,从另一个喷泉中找到距离他最远且还没用被标记的点,这个距离加前一个喷泉的距离就是要求的答案,选最小的即可,n方的时间复杂度. 需要注意的几点: 1.         对于每个点最好用…

题意: 有两个点喷水,有很多个点有花,给出坐标. 求使得每个花都可以被喷到,两个喷水的半径的平方的和最小是多少. 思路: 枚举其中一个喷水的最大半径. 坑: 这题我贪心的思路有很大问题.一开始也是想这样枚举的,但是思路超级混乱,按照r2进行贪心但是最后想想想法很荒谬. 顺序和题意一定要搞的很透彻才可以== #include<stdio.h> #include<string.h> #include<algorithm> using namespace std; struc…

题意: 有n朵花排成一排,小明要么吃掉连续的k朵白花,或者可以吃单个的红花. 给出一个n的区间[a, b],输出总吃花的方法数模 109+7 的值. 分析: 设d(i)表示吃i朵花的方案数. 则有如下递推关系: d[i] = d[i-1] + d[i-k], (i ≥ k, d[0] = 1) 我们在计数i+1的情况时,可以分为如下两种情况: 最后一朵是红花,方案数为d[i] 最后k朵是白花,方案数为d[i-k] 然后预处理一下前缀和. 代码中注意取模. #include <cstdio> +…

[链接] 我是链接,点我呀:) [题意] 让你吃东西 B食物一次必须要吃连续k个 但是对A食物没有要求 问你有多少种吃n个食物的方法(吃的序列) [题解] 设f[i]表示长度为i的吃的序列且符合要求的方法 有两种转移方法 一种是吃一个A食物 一种是吃k个食物 f[i] = f[i-1]+f[i-k] f[0] = 1 然后做一个前缀和输出区间和就好 [代码] import java.io.*; import java.util.*; public class Main { static Inpu…

[Codeforces Round #340 (Div. 2)] vp了一场cf..(打不了深夜的场啊!!) A.Elephant 水题,直接贪心,能用5步走5步. B.Chocolate 乘法原理计数,统计连续的“0”到下一个“1”的个数,然后相乘(第一个1前面的0不能算上).当然还要特判全0的情况. C.Watering Flowers 这题1A.只要按照以到某一个喷泉的距离排序,然后枚举没有被这一个喷泉覆盖到的个数,然后通过第二个喷泉覆盖,贪心一下就好了. D.Polyline 题意杀,还…

题目链接:Codeforces 451E Devu and Flowers 题目大意:有n个花坛.要选s支花,每一个花坛有f[i]支花.同一个花坛的花颜色同样,不同花坛的花颜色不同,问说能够有多少种组合. 解题思路:2n的状态,枚举说那些花坛的花取超过了,剩下的用C(n−1sum+n−1)隔板法计算个数.注意奇数的位置要用减的.偶数的位置用加的.容斥原理. #include <cstdio> #include <cstring> #include <cmath> #in…

E. Devu and Flowers 题目连接: http://codeforces.com/contest/451/problem/E Description Devu wants to decorate his garden with flowers. He has purchased n boxes, where the i-th box contains fi flowers. All flowers in a single box are of the same color (hen…

话说好久没写算法代码了,工作了有点忙的了.只是算法始终是我的挚爱,故此还是尽量抽时间和挚爱来个约会. Codeforces的题目是最适合练手的了,以下是一道不算难的动态规划法题目.先上题: D. Flowers time limit per test1.5 seconds memory limit per test256 megabytes inputstandard input outputstandard output We saw the little game Marmot made f…

题目链接:http://codeforces.com/problemset/problem/459/B 题意: 给出n支花,每支花都有一个漂亮值.挑选最大和最小漂亮值得两支花,问他们的差值为多少,并且有多少种选法(无先后顺序). 现场做时,想到的是:用multimap记录每个漂亮值出现的次数,并不断更新最大最小值. 这个方法很笨,而且multimap的val值是多余的. 需要注意特殊情况:max==min 代码如下: #include<iostream>//A - Pashmak and Fl…

题目链接:http://codeforces.com/problemset/problem/459/B 题目意思:有 n 朵 flowers,每朵flower有相应的 beauty,求出最大的beauty 差 和 要达到这个最大的差 的取法有多少种. 一下子wa,是因为没考虑到整个序列都是相同的beauty 时的情况,以为取法是一种= =.注意,beauty 差为0都是合法的.还有注意这句话:Two ways are considered different if and only if the…

D. Flowers time limit per test:1.5 seconds memory limit per test:256 megabytes We saw the little game Marmot made for Mole's lunch. Now it's Marmot's dinner time and, as we all know, Marmot eats flowers. At every dinner he eats some red and white flo…

time limit per test2 seconds memory limit per test256 megabytes inputstandard input outputstandard output Little Alyona is celebrating Happy Birthday! Her mother has an array of n flowers. Each flower has some mood, the mood of i-th flower is ai. The…

B. Alyona and flowers Problem Description: Let's define a subarray as a segment of consecutive flowers. The mother suggested some set of subarrays. Alyona wants to choose several of the subarrays suggested by her mother. After that, each of the flowe…

题 There are n sharks who grow flowers for Wet Shark. They are all sitting around the table, such that sharks i andi + 1 are neighbours for all i from 1 to n - 1. Sharks n and 1 are neighbours too. Each shark will grow some number of flowers si. For i…

题目链接:http://codeforces.com/problemset/problem/474/D 题目意思:Marmot 吃两种类型的花(实在难以置信呀--):red 或者 white,如果要吃到white这种花,就需要吃连续 k 朵 white:而如果吃 red,就没有这种限制.给定区间[a, b],问总共的吃法有多少种. dp 题!状态转移方程不难得到.设 dp[i] 表示 长度为 i 时 的吃法种数. dp[i] = dp[i-1] + dp[i-k] 对于当前 i,或者是从第 i-…

链接:http://codeforces.com/contest/322/problem/B 这题做错了.没考虑周全. #include <cstdio> #include <cstdlib> #include <iostream> #include <algorithm> using namespace std; int main(void) { int r, g, b; while (~scanf("%d%d%d", &r,…

题目链接:http://codeforces.com/problemset/problem/474/D 用RW组成字符串,要求w的个数要k个连续出现,R任意,问字符串长度为[a, b]时,字符串的种类有多少. 递推,dp[i]表示长度为i的种类有多少.当i < k的时候 dp[i] = 1 , 当i == k的时候 dp[i] = 2 ,  否则 dp[i] = dp[i - 1] + dp[i - k] . #include <bits/stdc++.h> using namespac…

http://codeforces.com/problemset/problem/474/D 思路:F[i]=F[i-1]+(i>=K)F[i-k] #include<cstdio> #include<cmath> #include<algorithm> #include<cstring> #include<iostream> ; ],f[]; int read(){ ,f=;char ch=getchar(); ;ch=getchar()…

D. Flowers time limit per test 1.5 seconds memory limit per test 256 megabytes input standard input output standard output We saw the little game Marmot made for Mole's lunch. Now it's Marmot's dinner time and, as we all know, Marmot eats flowers. At…

D. Flowers time limit per test 1.5 seconds memory limit per test 256 megabytes input standard input output standard output We saw the little game Marmot made for Mole's lunch. Now it's Marmot's dinner time and, as we all know, Marmot eats flowers. At…

题目链接:http://codeforces.com/problemset/problem/322/B 题目意思:给定红花.绿花和蓝花的朵数,问组成四种花束(3朵红花,3朵绿花,3朵蓝花,1朵红花+1朵绿花+1朵蓝花)的总数最大为多少. 一开始以为是水题,其实很多情况都没有考虑到,反反复复修改终于过了. 其实要考虑两种情况,这两种情况较好的那种就是最优解.姑且把四种花束分为两种类型:清一色型(3朵红,3朵绿,3朵蓝)和混杂型(红绿蓝各一朵). 第一种情况就是,保证清一色型最多(3种花都要除以3)…

Discription Devu wants to decorate his garden with flowers. He has purchased n boxes, where the i-th box contains fi flowers. All flowers in a single box are of the same color (hence they are indistinguishable). Also, no two boxes have flowers of the…

https://codeforces.com/problemset/problem/474/D 这道题挺好的,思路是这样. 我们要找一个01串,其中0的段要被划分为若干个连续k的0. 我们设想一个长度为n的合法串是怎么被构造出来的,要么是上一个合法串后面直接连接1,要么是上一个合法串后面连接k个连续的0,那么每个0一一对应于一段连续的0. 所以dp[i]=dp[i-1]+dp[i-k]. 想出来就觉得不难了. #include<bits/stdc++.h> using namespace st…

We saw the little game Marmot made for Mole's lunch. Now it's Marmot's dinner time and, as we all know, Marmot eats flowers. At every dinner he eats some red and white flowers. Therefore a dinner can be represented as a sequence of several flowers, s…

D. Flowers   We saw the little game Marmot made for Mole's lunch. Now it's Marmot's dinner time and, as we all know, Marmot eats flowers. At every dinner he eats some red and white flowers. Therefore a dinner can be represented as a sequence of sever…

[题目链接] http://codeforces.com/contest/451/problem/E [算法] 容斥原理 [代码] #include<bits/stdc++.h> using namespace std; typedef long long ll; ; int i,j,n,s,ans,MASK; ll m,t; ll a[],f[]; ]; inline int power(int a,int n) { ,b = a; while (n) { ) res = 1ll * res…