2136 Largest prime factor（打表）

Problem Description Everybody knows any number can be combined by the prime number.Now, your task is telling me what position of the largest prime factor.The position of prime 2 is 1, prime 3 is 2, and prime 5 is 3, etc.Specially, LPF(1) = 0. Input…

HDOJ(HDU) 2136 Largest prime factor(素数筛选)

Problem Description Everybody knows any number can be combined by the prime number. Now, your task is telling me what position of the largest prime factor. The position of prime 2 is 1, prime 3 is 2, and prime 5 is 3, etc. Specially, LPF(1) = 0. Inpu…

杭电 2136 Largest prime factor（最大素数因子的位置）

Largest prime factor Time Limit: 5000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 13481 Accepted Submission(s): 4765 Problem Description Everybody knows any number can be combined by the prime number.Now,…

HDU 2136 Largest prime factor （素数打表。。。）

题意:给你一个数,让你求它的最大因子在素数表的位置. 析:看起来挺简单的题,可是我却WA了一晚上,后来终于明白了,这个第一层循环不是到平方根, 这个题和判断素数不一样,只要明白了这一点,就很简单了. 代码如下: #include <iostream> #include <cstdio> #include <algorithm> #include <queue> #include <vector> #include <cstring>…

HDU 2136 Largest prime factor(查找素数，筛选法)

题目梗概:求1000000以内任意数的最大质因数是第几个素数,其中定义 1为第0个,2为第1个,以此类推. #include<string.h> #include<stdio.h> #include<math.h> ],b[],c[];//b[i]表示i是第几个素数,c[k]表示k的最大素数是c[k],a[i]表示是不是素数 int main() { int n,i,num,j; memset(a,,sizeof(a)); a[]=; b[]=; num=; ;i&l…

HDU 2136 Largest prime factor 參考代码

#include <iostream> #include <vector> #include <cmath> using namespace std; const int MAX=1000001; bool isPrime[MAX];//isPrime[i]=true表示是素数,false表示不是 int indexes[MAX]; //存放素数因子的序号 void eraosthenes() { fill(isPrime,isPrime+MAX,true);//如果0…

HDU 2136 Largest prime factor

题目大意:求出比给出数小的互质的质数个数. 题解:直接用筛法求素数,稍微改编一下,将原先的布尔数组变为数组用来记录信息就可以了. 注意点:大的数组定义要放在程序的开头,不要放在main里面,不然会栈溢出. #include <cstdio> #define max 1000000 }; int main() { int n; ; ; i<max; ++i) { if(prim[i]) continue; for(int j=i; j<max; j+=i) prim[j]=cnt;…

【沙茶了+筛选保存最大质因数】【HDU2136】Largest prime factor

Largest prime factor Time Limit: 5000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 6990 Accepted Submission(s): 2471 Problem Description Everybody knows any number can be combined by the prime number. Now…

【ACM】Largest prime factor

/*打表把素数能组合的数先设置成相应的位数*/ /* if n equals two and n is No.1 position of prime factors so four position of prime factors is no.1,as well*/ /* although two can combined six but three also can combined six */ /* and three position of prime factors is two…

[暑假集训--数论]hdu2136 Largest prime factor

Everybody knows any number can be combined by the prime number. Now, your task is telling me what position of the largest prime factor. The position of prime 2 is 1, prime 3 is 2, and prime 5 is 3, etc. Specially, LPF(1) = 0. InputEach line will con…

The largest prime factor（最大质因数）

1. 问题: The prime factors of 13195 are 5, 7, 13 and 29.What is the largest prime factor of the number 600851475143 ? 2. 解法(by java in Eclipse) package com.lun.alrithmetic; /* * Q1: what's the primary factor? (1 2 3) * Q2: i & i+2ne能否遍历出所有质数 */ public…

（Problem 3）Largest prime factor

The prime factors of 13195 are 5, 7, 13 and 29. What is the largest prime factor of the number 600851475143 ? #include<stdio.h> #include<string.h> #include<math.h> #include<ctype.h> #include<stdlib.h> #include<stdbool.h>…

Largest prime factor

problem 3:Largest prime factor 题意:求600851475143的最大的质因数代码如下: #ifndef PRO3_H_INCLUDED #define PRO3_H_INCLUDED #include "prime.h" namespace pro3{ long long solve(){ ;; ;i*i<=n;++i) ){ if(isPrime(n/i))return n/i; else if(isPrime(i))maxn=i; } >…

Problem 3: Largest prime factor

The prime factors of 13195 are 5, 7, 13 and 29. What is the largest prime factor of the number 600851475143 ? 欧拉题里很多是关于求质数,求质数的方法很多,我推荐的是筛选法,效率高,也很好理解.百度一下就有详细说明. def primeslist(max): a = [True]*(max+1) # 创建一个list,下标的位置就代表数字 a[0],a[1]=False,False # 0…

R语言学习——欧拉计划（3）Largest prime factor 求最大质因数

The prime factors of 13195 are 5, 7, 13 and 29. What is the largest prime factor of the number 600851475143 ? 翻译过后如下: 找出一个合数的最大质数因子 13195的质数因子有5,7,13和29. 600851475143的最大质数因子是多少? 做出答案以后的题解: 对于给定的n, 使factor = 2, 3, 4, 5, 6..., 对于每个factor, 当factor能被n完全整…

数学--数论--HDU2136 Largest prime factor 线性筛法变形

Problem Description Everybody knows any number can be combined by the prime number. Now, your task is telling me what position of the largest prime factor. The position of prime 2 is 1, prime 3 is 2, and prime 5 is 3, etc. Specially, LPF(1) = 0. Inpu…

水题第三站 HDU Largest prime factor

先写一遍思路,跟素数表很类似吧. 1)从小到大遍历数据范围内的所有数.把包含质因子的数的位置都设成跟质因子的位置相同. 2)同一个数的位置可能被多次复写.但是由于是从小到大遍历,这就保证了最后一次写入的是该数的最大质因子的位置一道题墨迹了好久,上代码分析 #include <iostream> #include <stdio.h> #include <math.h> #include <algorithm> #include <string.h>…

hdu Largest prime factor

类似于素数打表. #include <cstdio> #include <cstring> #include <algorithm> #define maxn 1000100 using namespace std; int f[maxn]; void inti() { ; ; i<maxn; i++) { ) { num++; for(int j=i; j<maxn; j+=i) { f[j]=num; } } } } int main() { int n…

[HDU2136] Largest prime factor（素数筛）

传送门题意给出若干个数n(n<=1000000),求每个n的最大质因子的排名. 质数的排名:如果素数p是第k小的素数,那么p的排名就是k. 思路乍一看不知道怎么搞. 其实可以想想我们怎么筛素数的,每个数都会被它的质因数筛去. 这就和题目一样了. 代码 #include <cstdio> ; ; int main() { int i, j, x; ; i < MAXN; i++) if(!notpri[i]) { for(j = i; j < MAXN; j += i)…

HD-ACM算法专攻系列（18）——Largest prime factor

题目描述: 源码: 需要注意,若使用cin,cout输入输出,会超时. #include"iostream" #include"memory.h" #define MAX 1000000 using namespace std; int index[MAX]; int main() { memset(index, -1, sizeof(index)); index[1] = 0; int sum = 0; for(int i = 2; i < MAX; i++…

（笔试题）质数因子Prime Factor

题目: Given any positive integer N, you are supposed to find all of its prime factors, and write them in the format N = p1^k1 * p2^k2 *...*pm^km. 输入描述: Each input file contains one test case which gives a positive integer N in the range of long int. 输出…