大意: 定义一个好数为位数为偶数, 且各位数字重排后可以为回文, 对于每个询问, 求小于$x$的最大好数. 假设$x$有$n$位, 若$n$为奇数, 答案显然为$n-1$个9. 若为偶数, 我们想让答案尽量大, 那么就要尽量调整$x$的低位数, 从低位到高位遍历, 假设当前处理到第$i$位, 对于判断重排后回文可以用一个长为10的二进制数来判断, 假设$[i+1,n]$状态为$t$, 那么问题就转化为求最大的小于$t$且二进制状态为$s$的数, 贪心填数即可, 若对于每一位都无解答案就为$n-2…

题意:给定一个长度为偶数的数,输出小于它的最大的美丽数.如果一个数长度为偶数,且没有前导零,并存在一种排列是回文数的数为美丽数.给定的t个数长度总和不超过200000. 分析: 1.存在一种排列为回文数,即这个数包含的数字都是偶数个. 2.预处理出每个数字的个数. 3.从最右边一位依次往左枚举,当逐渐减小第i位时,统计目前的数中,第i位之前有多少个数字是奇数个,记为cnt. 4.因为第i位之后的数字可以随便填,所以如果第i位之后数字的个数大于等于cnt,那么则可以得出答案,大于的部分先用9填充,…

题: OvO http://codeforces.com/contest/946/problem/E CF 946E 解: 记读入串为 s ,答案串为 ans,记读入串长度为 len,下标从 1 开始. 分三种情况讨论 1.数字位数为奇数,设数字位数为 len,则输出 ( len-1 ) 个 9 即可 ,最低位为 或者,其他位为 ,(即 100001,100 这些形式),记数字位数为 len,则输出 ( len-2 ) 个 9 即可 3.数字位数为偶数,而并非是第二种情况,那么进行一次 dfs…

大意: 给定序列$a$, 可以任意排序, 求最大下标i的个数, 满足$a_i<a_{i+1}$. 这个贪心挺好的, 答案就为n-所有数字出现次数最大值.…

Codeforces 55D Beautiful Number a positive integer number is beautiful if and only if it is divisible by each of its nonzero digits. Input The first line of the input contains the number of cases t (1 ≤ t ≤ 10). Each of the next t lines contains two…

题目链接: http://codeforces.com/problemset/problem/55/D 数位DP 题目描述: 一个数能被它每位上的数字整除(0除外),那么它就是beautiful number.问区间[a,b]上有多少个beautiful number.如102就是一个beautiful number,因为它能整除1,2.14不是,因为14不能整除4. 解法: 数位DP,设dp[i][j][k]为累计到第i为,公倍数为j,模lcm(1,2,```,9)=2520的余数为k的数的个…

Vasya and Beautiful Arrays CodeForces - 354C Vasya's got a birthday coming up and his mom decided to give him an array of positive integers a of length n. Vasya thinks that an array's beauty is the greatest common divisor of all its elements. His mom…

D - Beautiful Graph CodeForces - 1093D You are given an undirected unweighted graph consisting of nn vertices and mm edges. You have to write a number on each vertex of the graph. Each number should be 11, 22or 33. The graph becomes beautiful if for…

题目链接: http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=2829 题目描述: Mike is very lucky, as he has two beautiful numbers, 3 and 5. But he is so greedy that he wants infinite beautiful numbers. So he declares that any positive number which is…

Beautiful Number Time Limit: 2 Seconds      Memory Limit: 65536 KB Mike is very lucky, as he has two beautiful numbers, 3 and 5. But he is so greedy that he wants infinite beautiful numbers. So he declares that any positive number which is dividable…

beautiful number 问题描述 令 A = \sum_{i=1}^{n}a_i * {10}^{n-i}(1\leq a_i \leq 9)A=∑​i=1​n​​a​i​​∗10​n−i​​(1≤a​i​​≤9)(nn为AA的位数).若AA为“漂亮的数”当且仅当对于任意1 \leq i < n1≤i<n满足a[i] \geq a[i+1]a[i]≥a[i+1]且对于任意1 \leq i \leq n,i < j \leq n1≤i≤n,i<j≤n,满足a[i]a[i]…

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=2829 Beautiful Number Time Limit: 2 Seconds      Memory Limit: 65536 KB Mike is very lucky, as he has two beautiful numbers, 3 and 5. But he is so greedy that he wants infinite beautiful nu…

beautiful number Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 801    Accepted Submission(s): 518 Problem Description Let A=∑ni=1ai∗10n−i(1≤ai≤9)(n is the number of A's digits). We call A as “…

把数位dp写成记忆化搜索的形式,方法很赞,代码量少了很多. 下面为转载内容:  a positive integer number is beautiful if and only if it is divisible by each of its nonzero digits.    问一个区间内[l,r]有多少个Beautiful数字    范围9*10^18        数位统计问题,构造状态也挺难的,我想不出,我的思维局限在用递推去初始化状态,而这里的状态定义也比较难    跟pre的…

Some natural number was written on the board. Its sum of digits was not less than k. But you were distracted a bit, and someone changed this number to n, replacing some digits with others. It's known that the length of the number didn't change. You h…

B. Split a Number time limit per test2 seconds memory limit per test512 megabytes inputstandard input outputstandard output Dima worked all day and wrote down on a long paper strip his favorite number n consisting of l digits. Unfortunately, the stri…

题目链接:https://codeforces.com/contest/1265/problem/C 题意 从大到小给出 $n$ 只队伍的过题数,要颁发 $g$ 枚金牌,$s$ 枚银牌,$b$ 枚铜牌,要求: $g < s, g < b$ $g + s + d \le \lfloor \frac{n}{2} \rfloor$ 金牌队伍的过题数大于银牌,银牌队伍的过题数大于铜牌 输出颁发奖牌数最多的一种方案. 题解 根据第三个要求,奖牌一定是按过题数的大小颁发的. 金牌只颁发给过题最多数的队伍,…

题目大意: 求  1(m)到n直接有多少个数字x满足 x可以整出这个数字的每一位上的数字 思路: 整除每一位.只需要整除每一位的lcm即可 但是数字太大,dp状态怎么表示呢 发现 1~9的LCM 是2520 ....也就是说只要对这个数mod2520 剩下的余数能整除lcm就可以整除了.. 计数的时候还有一个技巧,具体见注释 此外这个题还卡常数了,预处理lcm才过了.. 代码如下: #include <iostream> #include <stdio.h> #include<…

题意及思路:https://www.cnblogs.com/liuzhanshan/p/6560499.html 这个做法的复杂度看似是O(n ^ 2),实际上均摊是O(n)的.我们考虑两种极端数据:一种是全是2,那么去重后实际上只有一个数.这样是O(n)的.另一种是所有的数都不一样,那么为了让最大的那个最小,数分别为2, 3 ...1e5, 1e5 + 1, 但是a和b之差最多只有1e6,这种情况甚至比刚才那种耗时更少.故复杂度均摊是O(n)的. 代码: #include <bits/stdc…

There are n people and k keys on a straight line. Every person wants to get to the office which is located on the line as well. To do that, he needs to reach some point with a key, take the key and then go to the office. Once a key is taken by somebo…

Arkady needs your help again! This time he decided to build his own high-speed Internet exchange point. It should consist of n nodes connected with minimum possible number of wires into one network (a wire directly connects two nodes). Exactly k of t…

题目链接:http://codeforces.com/problemset/problem/93/B B. End of Exams time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Students love to celebrate their holidays. Especially if the holiday is th…

Megacity Time Limit: 2000MS   Memory Limit: 262144KB   64bit IO Format: %I64d & %I64u Submit Status Description The administration of the Tomsk Region firmly believes that it's time to become a megacity (that is, get population of one million). Inste…

http://codeforces.com/problemset/problem/893/D 题意 Recenlty Luba有一张信用卡可用,一开始金额为0,每天早上可以去充任意数量的钱.到了晚上,银行会对信用卡进行一次操作,操作有三种操作. 1.如果a[i]>0,银行会给卡充入a[i]元. 2.如果a[i]<0 银行从卡中扣除a[i]元. 3.如果a[i]=0 银行会查询卡里的金额. 有两条规则,如果违背信用卡就会被冻结. 1.信用卡里的金额不能大于d. 2.当银行查询卡里的金额时,金额不…

Description There is a special number sequence which has n+1 integers. For each number in sequence, we have two rules: ● a i ∈ [0,n] ● a i ≠ a j( i ≠ j ) For sequence a and sequence b, the integrating degree t is defined as follows(“�” denotes exclus…

Given a collection of number segments, you are supposed to recover the smallest number from them. For example, given { 32, 321, 3214, 0229, 87 }, we can recover many numbers such like 32-321-3214-0229-87 or 0229-32-87-321-3214 with respect to differe…

Maxim always goes to the supermarket on Sundays. Today the supermarket has a special offer of discount systems. There are m types of discounts. We assume that the discounts are indexed from 1 to m. To use the discount number i, the customer takes a s…

C - Ordering Pizza CodeForces - 867C C - Ordering Pizza 这个是最难的,一个贪心,很经典,但是我不会,早训结束看了题解才知道怎么贪心的. 这个是先假设每个人都可以吃到他喜欢的,就是先求出答案,然后按照b-a 排序,分别放入两个优先队列里面, 如果b>a 那就吃第二块,否则就吃第一块,求出num,注意优先队列按照从小到达排序. num1记录第一块吃的数量,num2记录第二块吃的数量. num1%=s,num2%=s  如果num1+num2的数…

作者: 负雪明烛 id: fuxuemingzhu 个人博客:http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 桶排序 日期 题目地址:https://leetcode-cn.com/problems/check-if-a-number-is-majority-element-in-a-sorted-array/ 题目描述 Given an array of integers A`, return the largest integer that only oc…

题目:http://codeforces.com/contest/570/problem/C 题意:给你一个字符串,由‘.’和小写字母组成.把两个相邻的‘.’替换成一个‘.’,算一次变换.现在给你一些个操作,操作内容是把某个位置的字符变成给定的 字符,求出每次操作后,需要多少次 变换才能把原串所有相邻的‘.’变成一个‘.’.注意,每次操作是累加的,即一次操作就会把原串替换一个字符. 分析:先求出原串的变换次数sum,然后每次询问的时候,直接看他的两边是否是".",如果是".&…