题意:给你两个正整数a和b,询问q次,每次给你一个区间[l,r],问[l,r]中有多少数字满足:x%a%b!=a%b%a. 题解:看公式无从下手的题,一般都是要找规律的.首先,我们知道,假如x%a%b!=x%b%a,那么:(x+lcm(a,b))%a%b!=(x+lcm(a,b))%b%a,(这个知识在exgcd中很常用).所以,我们打表发现,这其实是一个循环节的问题. 首先枚举[1,lcm]中有多少不相同的,然后每次询问,我们处理一下区间就好了,公式:(r/lcm-(l-1)/lcm)*num…

The Counting Problem 询问区间\([a,b]\)中\(1\sim 9\)出现的次数,0 < a, b < 100000000. 解 显然为数位递推,考虑试填法,现在关键是求出方案数,于是设\(A[i]\)表示i位以内数字中0出现的次数,不含前导0,\(B[i]\)为i位数字中\(0\sim 9\)出现的次数,可以含前导0,不难有(其中\(base[i]=10^i\)),显然有 \[B[i]=10\times B[i-1]+base[i-1]\] \[A[i]=A[i-1]+…

Educational Codeforces Round 40 F. Runner's Problem 题意: 给一个$ 3 * m \(的矩阵,问从\)(2,1)$ 出发 走到 \((2,m)\) 的方案数 \(mod 1e9 + 7\), 走的规则和限制如下: From the cell (i, j) you may advance to: (i - 1, j + 1) - only if i > 1, (i, j + 1), or (i + 1, j + 1) - only if i <…

/** 题目:UVA 1640 The Counting Problem UVA1640 链接:https://vjudge.net/problem/UVA-1640 题意:求[a,b]或者[b,a]区间内0~9在里面各个数的数位上出现的总次数. 思路:数位dp: dp[leadzero][i][j][k]表示前面是否选过非0数,即i长度之后可以第一个出现0,而不是前导0,长度为i,前面出现j,k次,j出现的次数. */ #include<iostream> #include<cstri…

The Counting Problem Description 求 [L,R]内每个数码出现的次数. Input Format 若干行,一行两个正整数 L 和 R. 最后一行 L=R=0,表示输入结束. Output Format 若干行,对于每个询问做出回答,每行 10 个整数,依次表示 0 至 9 出现的次数. 输入的最后一行不属于询问,因此不必对此做出回答. Sample Input 1 10 114 514 233 666 19260421 19260817 19190504 1989…

题意 Language:DefaultEspañol The Counting Problem Time Limit: 3000MS Memory Limit: 65536K Total Submissions: 5070 Accepted: 2590 Description Given two integers a and b, we write the numbers between a and b, inclusive, in a list. Your task is to calcula…

\(给出a,b,l,r,求在区间[l,r]内有多少x满足x%a%b!=x%b%a\) \(--------------------分割!!~----------------------------\) \(打个表很快发现规律,以a*b为循环节,每个循环节内满足条件的数都相同,那直接前缀和查询\) \(算出[1,r]满足条件的数,算出[1,l-1]满足条件的数,相减即可\) #include <bits/stdc++.h> using namespace std; typedef long lo…

A - Noldbach problem 题面链接 http://codeforces.com/contest/17/problem/A 题面 Nick is interested in prime numbers. Once he read about Goldbach problem. It states that every even integer greater than 2 can be expressed as the sum of two primes. That got Nic…

A. Hanoi tower Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/gym/100114 Description you the conditions of this task. There are 3 pivots: A, B, C. Initially, n disks of different diameter are placed on the pivot A: the smallest dis…

BOPCTime Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://acm.hust.edu.cn/vjudge/contest/view.action?cid=86686#problem/D Description You invented a new chess figure and called it BOPC. Suppose it stands at the square grid at the point with coordinates …