Codeforces 385C Bear and Prime Numbers 其实不是多值得记录的一道题,通过快速打素数表,再做前缀和的预处理,使查询的复杂度变为O(1). 但是,我在统计数组中元素出现个数时使用了map,以至于后面做前缀和的累加时,每次都要对map进行查询,以至于TLE.而自己一直没有发现,以为是欧拉筛对于这道题还不够优,于是上网搜题解,发现别人的做法几乎一样,但是却能跑过,挣扎了许久才想起是map的原因.map的内部实现是一颗红黑树,每次查询的复杂度为O(logN),在本来时…
第一眼看这道题目的时候觉得可能会很难也看不太懂,但是看了给出的Hint之后思路就十分清晰了 Consider the first sample. Overall, the first sample has 3 queries. The first query l = 2, r = 11 comes. You need to count f(2) + f(3) + f(5) + f(7) + f(11) = 2 + 1 + 4 + 2 + 0 = 9. The second query comes…
385C - Bear and Prime Numbers 思路:记录数组中1-1e7中每个数出现的次数,然后用素数筛看哪些能被素数整除,并加到记录该素数的数组中,然后1-1e7求一遍前缀和. 代码: #include<bits/stdc++.h> using namespace std; #define ll long long #define pb push_back #define mem(a,b) memset((a),(b),sizeof(a)) const int INF=0x3f…
Recently, the bear started studying data structures and faced the following problem. You are given a sequence of integers x1, x2, ..., xn of length n and m queries, each of them is characterized by two integers li, ri. Let's introduce f(p) to represe…
题意翻译 给你一串数列a.对于一个质数p,定义函数f(p)=a数列中能被p整除的数的个数.给出m组询问l,r,询问[l,r]区间内所有素数p的f(p)之和. 题目描述 Recently, the bear started studying data structures and faced the following problem. You are given a sequence of integers x1,x2,...,xn x_{1},x_{2},...,x_{n} x1,x2,.…
Problem Description Give you a lot of positive integers, just to find out how many prime numbers there are. Input There are a lot of cases. In each case, there is an integer N representing the number of integers to find. Each integer won't exceed 32-…
Almost prime numbers are the non-prime numbers which are divisible by only a single prime number.In this problem your job is to write a program which finds out the number of almost prime numberswithin a certain range.InputFirst line of the input file c…
A - Bear and Prime 100 思路:任何一个合数都可以写成2个以上质数的乘积.在2-100中,除了4,9,25,49外都可以写成两个以上不同质数的乘积. 所以打一个质数加这四个数的表:{2,3,4,5,7,9,11,13,17,19,23,25,29,31,37,41,43,47,49},询问19次,如果能被整出两次以上,说明是合数,否则是质数. #include<bits/stdc++.h> using namespace std; #define ll long long…
Sum of Consecutive Prime Numbers Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 19697 Accepted: 10800 Description Some positive integers can be represented by a sum of one or more consecutive prime numbers. How many such representatio…
题目链接: A. Mashmokh and Numbers time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output It's holiday. Mashmokh and his boss, Bimokh, are playing a game invented by Mashmokh. In this game Mashmokh wri…
C. Bear and Prime 100 time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output This is an interactive problem. In the output section below you will see the information about flushing the output. Bea…
C. Bear and Prime 100 题目连接: http://www.codeforces.com/contest/680/problem/C Description This is an interactive problem. In the output section below you will see the information about flushing the output. Bear Limak thinks of some hidden number - an i…
Sieve of Eratosthenes (素数筛选算法) Given a number n, print all primes smaller than or equal to n. It is also given that n is a small number. For example, if n is 10, the output should be “2, 3, 5, 7″. If n is 20, the output should be “2, 3, 5, 7, 11, 13,…
题目链接: C. Bear and Prime 100 time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output This is an interactive problem. In the output section below you will see the information about flushing the outpu…
C. Bear and Prime 100 time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output This is an interactive problem. In the output section below you will see the information about flushing the output. Bea…
Description Some positive integers can be represented by a sum of one or more consecutive prime numbers. How many such representations does a given positive integer have? For example, the integer 53 has two representations 5 + 7 + 11 + 13 + 17 and 53…
How many prime numbers Time Limit: 3000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 12955 Accepted Submission(s): 4490 Problem Description Give you a lot of positive integers, just to find out how many…
Sum of Consecutive Prime Numbers Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 19895 Accepted: 10906 Description Some positive integers can be represented by a sum of one or more consecutive prime numbers. How many such representatio…
解题思路:给定一个数,判定它由几个连续的素数构成,输出这样的种数 用的筛法素数打表 Sum of Consecutive Prime Numbers Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 20020 Accepted: 10966 Description Some positive integers can be represented by a sum of one or more consecutive…
