Description Write a program which reads an integer n and prints the number of prime numbers which are less than or equal to n. A prime number is a natural number which has exactly two distinct natural number divisors: 1 and itself. For example, the f…

平衡数的定义是指,以某位作为支点,此位的左面(数字 * 距离)之和 与右边相等,距离是指某位到支点的距离; 题意:求区间内满足平衡数的数量 : 分析:很好这又是常见的数位dp , 不过不同的是我们这次需要枚举是哪个位置是平衡点 , 一开始我是想说搜索到最后以为 ,然后得到这个数的位数 ,在判断平衡位置 , 想到这样的话 , 这就说明了我对数位dp 还是不太熟悉的 ,因为这样的话dfs() 里面的sum , emmm是找不到状态的 : 正解: 依然是枚举平衡点的位置  ,这个思路没有问题 , 但是…

参考链接:https://blog.csdn.net/Dylan_Frank/article/details/54428481 #include <bits/stdc++.h> #define ll long long using namespace std; ll f[340000],g[340000],n; void init(){ ll i,j,m; for(m=1;m*m<=n;++m)f[m]=n/m-1; for(i=1;i<=m;++i)g[i]=i-1; for(i…

http://acm.hust.edu.cn/vjudge/problem/viewProblem.action?id=34870 求n内的素数个数. /* *********************************************** Author : zch Created Time :2015/5/19 8:46:16 File Name :a.cpp ************************************************ */ #include…

Given two integers L and R, find the count of numbers in the range [L, R] (inclusive) having a prime number of set bits in their binary representation. (Recall that the number of set bits an integer has is the number of 1s present when written in bin…

Given two integers L and R, find the count of numbers in the range [L, R] (inclusive) having a prime number of set bits in their binary representation. (Recall that the number of set bits an integer has is the number of 1s present when written in bin…

［抄题］: Given two integers L and R, find the count of numbers in the range [L, R] (inclusive) having a prime number of set bits in their binary representation. (Recall that the number of set bits an integer has is the number of 1s present when written…

时间限制:1 秒 内存限制:32 兆 特殊判题:否 提交:5278 解决:2180 题目描述: Output the k-th prime number. 输入: k≤10000 输出: The k-th prime number. 样例输入: 3 7 样例输出: 5 17 来源: 2008年上海交通大学计算机研究生机试真题 思路: 求质数要注意时间复杂度,只需要搜到sqrt(n)即可判断是否为质数. 另外如果多次求解,可以预先存数组,这样避免多次求解. 代码: #include <stdio.…

题目链接:contest=0&problem=231">点击打开链接 题意: 求<=n内有多少对素数(a,b)使得a+b也为素数 思路: 我们发现全部素数间隔都是>=2的,且除了2都是奇数.那么: 奇数+奇数 = 偶数. 所以仅仅有一种情况2+素数=素数. 所以打个素数表,看一下有多少个素数和前面那个素数间隔是2的. #include <stdio.h> #include <string.h> #include <iostream>…

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 遍历数字+质数判断 日期 题目地址:https://leetcode.com/problems/prime-number-of-set-bits-in-binary-representation/description/ 题目描述 Given two integers L and R, find the count of numbers in the…