题目链接:http://poj.org/problem?id=3252 题意: 一个数的二进制表示中0的个数大于等于1的个数则称作Round Numbers.求区间[L,R]内的 Round Numbers的个数. 思路: int c[N][N]; void init(){    int i,j;    FOR0(i,N)     {        c[i][0]=c[i][i]=1;        for(j=1;j<i;j++) c[i][j]=c[i-1][j-1]+c[i-1][j]; …

Round Numbers Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 8590   Accepted: 3003 Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Scissors',…

Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 7558   Accepted: 2596 Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Scissors', 'Ro, Sham, Bo'…

Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 13381   Accepted: 5208 Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Scissors', 'Ro, Sham, Bo…

 组合数学...(每做一题都是这么艰难) Round Numbers Time Limit: 2000MS Memory Limit: 65536K Total Submissions: 7607 Accepted: 2615 Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, P…

Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Scissors', 'Ro, Sham, Bo', and a host of other names) in order to make arbitrary decisions such as who gets…

Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Scissors', 'Ro, Sham, Bo', and a host of other names) in order to make arbitrary decisions such as who gets…

Round Numbers Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 10223   Accepted: 3726 Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Scissors',…

题目链接:[kuangbin带你飞]专题十五 数位DP E - Round Numbers 题意 给定区间.求转化为二进制后当中0比1多或相等的数字的个数. 思路 将数字转化为二进制进行数位dp,由于一个二进制数的最高位必须为1.所以设置变量first记录前面位是否有1,若有1,则可随意放,否则,仅仅可放1. 同一时候.上面的推断决定了搜索时len的大小与二进制本身的长度不一定相等,所以需两个变量对1和0的个数进行记录. 用dp[a][b][c]保存长度a,b个0,c个1的数字个数.记忆化搜索.…

链接: https://vjudge.net/problem/POJ-3252 题意: The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Scissors', 'Ro, Sham, Bo', and a host of other names) in order to make arbit…

以sample为例子 [2,12]区间的RoundNumbers(简称RN)个数:Rn[2,12]=Rn[0,12]-Rn[0,1] 即:Rn[start,finish]=Rn[0,finish]-Rn[0,start-1] 所以关键是给定一个X,求出Rn[0,X] 现在假设X=10100100  这个X的二进制总共是8位,任何一个小于8位的二进制都小于X 第一部分,求出长度为[0,7]区间内的二进制是RoundNumber的个数  对于一个长度为Len的二进制(最高位为1),如何求出他的Rou…

题意:给定区间[l,r],l < r ,求区间中满足条件的正整数的个数:二进制表示下0的个数不少于1的个数. 分析:f(x)表示<=x时满足条件的数的个数,所求问题即为f(r)-f(l-1).x二进制表示下从高到低位为1,bi,bi-1, bi-2, b0, 长度为len, 那么f(x)可以这样求解: dp[i][j]表示从i~0位可以任意为0或1时,0的个数比1多j个情况,由于j可能为负数,所以这里方便处理,将j = 40表示0的个数和1的个数一样多. 转移:dp[i][j] = sum{d…

题目链接 找一个范围内二进制中0的个数大于等于1的个数的数的数量.基础的数位dp #include<bits/stdc++.h> using namespace std; #define mem1(a) memset(a, -1, sizeof(a)) ], dp[][][], len; int dfs(int len, int num0, int num1, int f, int first) { //first记录前面是否全部为0 if(!len) { return num0>=nu…

题意: 统计区间[L,R]有多少个数,其二进制表示法中的0的个数不少于1的个数?(不允许前缀0) 思路: 状态表示为 [当前第几位][总位数][1的个数],最后判断一下1的个数是否满足条件,要注意前导0的问题,可以通过枚举二进制的位数来解决. //#include <bits/stdc++.h> #include <iostream> #include <cstdio> #include <cstring> #include <cmath> #i…

正解:数位$dp$ 解题报告: 传送门$w$ 沉迷写博客,,,不想做题,,,$QAQ$口胡一时爽一直口胡一直爽$QAQ$ 先港下题目大意嗷$QwQ$大概就说,给定区间$[l,r]$,求区间内满足二进制中0的个数小于等于1的个数的数个数 数位$dp$板子,,,? 首先区间转成$[1,r]-[1,l-1]$然后十进制转二进制这个就不港了,,, 然后就考虑$dfs$中要记录哪些东西$QwQ$? 首先依然是一个$pos$一个$lim$,因为01的个数对结果会有影响,所以显然考虑还要记一个$num$表示实…

题意:一条整数链,要求相邻两数前一个整除后一个.给出链尾的数,求链的最大长度以及满足最大长度的不同链的数量. 类型:因式分解+排列组合 算法:因式分解的素因子个数即为链长,链中后一个数等于前一个数乘以某素因子,所以链的数量即为这些因子不全相异的全排列数:A!/(a1!a2!a3!..) #include <cstdio> #include <cmath> #include <iostream> using namespace std; typedef long long…

Round Numbers Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 6983   Accepted: 2384 Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Scissors',…

题目链接:http://poj.org/problem?id=3252 Round Numbers Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 14640   Accepted: 5881 Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (al…

POJ 3252:Round Numbers Time Limit: 2000MS Memory Limit: 65536K Total Submissions: 10099 Accepted: 3669 Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Sciss…

The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Scissors', 'Ro, Sham, Bo', and a host of other names) in order to make arbitrary decisions such as who gets to be milked…

C. Kyoya and Colored Balls Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/554/problem/C Description Kyoya Ootori has a bag with n colored balls that are colored with k different colors. The colors are labeled from 1 to k.…

Round Numbers Time Limit : 4000/2000ms (Java/Other)   Memory Limit : 131072/65536K (Java/Other) Total Submission(s) : 11   Accepted Submission(s) : 8 Problem Description The cows, as you know, have no fingers or thumbs and thus are unable to play Sci…

Round Numbers http://poj.org/problem?id=3252 Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 17293   Accepted: 7188 Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also kn…

一般用dfs来做 最简单的一种: 17. Letter Combinations of a Phone Number Given a digit string, return all possible letter combinations that the number could represent. A mapping of digit to letters (just like on the telephone buttons) is given below. Input:Digit s…

今天,隔壁坐的小朋友给我一串数字: 1 6 21 55 让我观察规律,然后帮他推导公式. 尼玛,当我是神呢?!! 想了半天没看出个原委, 于是看了他那边具体需要才发现他那边是对N个数字进行5个数字的组合, 有多少种可能性的计算. 我一想,这不是初中学过的排列组合公式么. 显然,我忘记了,呵呵. 只记得大概是叫Pmn. 然后通过搜索引擎看到如下百度百科里面排列组合的几十这里: http://baike.baidu.com/item/%E6%8E%92%E5%88%97%E7%BB%84%E5%90…

国庆期间,省城刚刚举行了一场盛大的集体婚礼,为了使婚礼进行的丰富一些,司仪临时想出了有一个有意思的节目,叫做"考新郎",具体的操作是这样的: 首先,给每位新娘打扮得几乎一模一样,并盖上大大的红盖头随机坐成一排; 然后,让各位新郎寻找自己的新娘.每人只准找一个,并且不允许多人找一个. 最后,揭开盖头,如果找错了对象就要当众跪搓衣板... 看来做新郎也不是容易的事情... 假设一共有N对新婚夫妇,其中有M个新郎找错了新娘,求发生这种情况一共有多少种可能. Input 输入数据的第一行是一个…

[容斥原理] 对于统计指定排列方案数的问题,一个方案是空间中的一个元素. 定义集合x是满足排列中第x个数的限定条件的方案集合,设排列长度为S,则一共S个集合. 容斥原理的本质是考虑[集合交 或 集合交的补集]和[集合并 或 集合并的补集]之间相互转化的问题. 定义目标函数为f(m),已知函数g(T).(例如已知集合并,则T表示所有T个集合的集合并,通常g(T)=C(n,T)*T个集合的集合并) 当两者都不是补集或两者都是补集时,有f(S)=Σ(-1)|T|-1g(T),其中T为S的非空子集,即奇…

题目链接 Problem Description You are given a permutation a from 0 to n−1 and a permutation b from 0 to m−1. Define that the domain of function f is the set of integers from 0 to n−1, and the range of it is the set of integers from 0 to m−1. Please calcul…

1801: Mr. S’s Romance Time Limit: 1 Sec  Memory Limit: 128 MBSubmit: 15  Solved: 5[Submit][Status][Web Board] Description Mr. S is a young math professor who is famous for being crazy about collecting prime numbers. Once he met a number, he would fir…

Given two integers n and k, return all possible combinations of k numbers out of 1 ... n. For example,If n = 4 and k = 2, a solution is: [ [2,4], [3,4], [2,3], [1,2], [1,3], [1,4], ] 就是排列组合的问题,使用dfs就可以解决,代码如下: class Solution { public: vector<vector<…