4877 Non-Decreasing Digits A number is said to be made up ofnon-decreasing digitsif all the digits to theleftof any digit is lessthan or equal to that digit. For example, the four-digit number 1234 is composed of digits that arenon-decreasing. Some o…

传送门:BNUOJ 52325 Increasing or Decreasing题意:求[l,r]非递增和非递减序列的个数思路:数位dp,dp[pos][pre][status] pos:处理到第几位 pre:前一位是什么 status:是否有前导零 递增递减差不多思路,不过他们计算的过程中像5555,444 这样的重复串会多算,所以要剪掉.个数是(pos-1)*9+digit[最高位],比如一位重复子串是:1,2,3,4...9,9个,二位重复子串:11,22,33,44,...,99,9个:…

题目链接: http://acm.hust.edu.cn/vjudge/problem/48419 Odd and Even Zeroes Time Limit: 3000MS 问题描述 In mathematics, the factorial of a positive integer number n is written as n! and is defined as follows: n! = 1 × 2 × 3 × 4 × . . . × (n − 1) × n = ∏n i=1 i…

题目链接: http://acm.hust.edu.cn/vjudge/problem/113727 Restaurant Ratings Time Limit: 3000MS 题意 给你一个长度为n,由非负整数组成的和为sum的序列.求长度为也为n,且和比sum小的或者和等于sum并且字典序小于所给序列的所有不同的序列. 题解 数位dp. dp[i][j]表示序列长度为i时和为j的所有不同序列数. sumv[i][j]表示长度为i并且和小于等于j的所有不同序列数. 代码 #include<ma…

在了解数位dp之前,先来看一个问题: 例1.求a~b中不包含49的数的个数. 0 < a.b < 2*10^9 注意到n的数据范围非常大,暴力求解是不可能的,考虑dp,如果直接记录下数字,数组会开不起,该怎么办呢?要用到数位dp. 数位dp一般应用于: 求出在给定区间[A,B]内,符合条件P(i)的数i的个数. 条件P(i)一般与数的大小无关,而与 数的组成 有关. 这样,我们就要考虑一些特殊的记录方法来做这道题.一般来说,要保存给定数的每个位置的数.然后要记录的状态为当前操作数的位数,剩下的…

http://www.codeforces.com/gym/100827/attachments Hill Number Time Limits:  5000 MS   Memory Limits:  200000 KB 64-bit interger IO format:  %lld   Java class name:  Main Description A Hill Number is a number whose digits possibly rise and then possibl…

SRM 510 2 250TheAlmostLuckyNumbersDivTwo Problem Statement John and Brus believe that the digits 4 and 7 are lucky and all others are not. According to them, an almost lucky number is a number that contains at most one non-lucky digit in its decimal…

K-wolf Number Problem Description   Alice thinks an integer x is a K-wolf number, if every K adjacent digits in decimal representation of x is pairwised different.Given (L,R,K), please count how many K-wolf numbers in range of [L,R].   Input   The in…

题目链接:http://acm.split.hdu.edu.cn/showproblem.php?pid=4734 F(x) Time Limit: 1000/500 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 4389    Accepted Submission(s): 1614 Problem Description For a decimal number x with…

Contest Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 220    Accepted Submission(s): 88 Problem Description In the ACM International Collegiate Programming Contest, each team consist of three…