UVa 583-Prime Factors

最新推荐文章于 2018-02-20 08:59:44 发布

AcToy

最新推荐文章于 2018-02-20 08:59:44 发布

阅读量654

点赞数

分类专栏：数论

本文链接：https://blog.youkuaiyun.com/AcToy/article/details/9008523

版权

数论专栏收录该内容

26 篇文章

订阅专栏

质数分解，将Case的所有因子全部输出即可

/*************************************************************************
    > File Name: 583.cpp
    > Author: Toy
    > Mail: ycsgldy@163.com 
    > Created Time: 2013年06月02日 星期日 16时02分48秒
 ************************************************************************/

#include <algorithm>
#include <iostream>
#include <iomanip>
#include <cstring>
#include <cstdlib>
#include <climits>
#include <sstream>
#include <fstream>
#include <cstdio>
#include <string>
#include <vector>
#include <queue>
#include <cmath>
#include <stack>
#include <map>
#include <set>

using namespace std;
const int INF = 0x7fffffff;
typedef pair<int,int> II;
typedef vector<int> IV;
typedef vector<II> IIV;
typedef vector<bool> BV;
typedef long long i64;
typedef unsigned long long u64;
typedef unsigned int u32;
#define For(t,v,c) for(t::const_iterator v=c.begin(); v!=c.end(); ++v)
#define IsComp(n) (_c[n>>6]&(1<<((n>>1)&31)))
#define SetComp(n) _c[n>>6]|=(1<<((n>>1)&31))
const int MAXP = 46341; //sqrt(2^31)
const int SQRP = 216; //sqrt(MAX)
int _c[(MAXP>>6)+1];
IV primes;
IIV opt;

void prime_sieve ( ) {
	for ( int i = 3; i <= SQRP; i += 2 ) 
		if ( !IsComp ( i ) ) for ( int j = i * i; j <= MAXP; j += i + i ) SetComp ( j );
	primes.push_back ( 2 );
	for ( int i = 3; i <= MAXP; i += 2 ) if ( !IsComp ( i ) ) primes.push_back ( i );
}

void prime_factorize ( int n, IIV &f ) {
	opt.clear();
	int sn = sqrt ( n );
	For ( IV, it, primes ) {
		int prime = *it;
		if ( prime > sn ) break; if ( n % prime ) continue;
		int e = 0; for ( ; n % prime == 0; e++, n /= prime ) ;
		f.push_back ( II ( prime, e ) );
	}
	if ( n > 1 ) f.push_back ( II ( n, 1 ) );
}

int Case;
int main ( ) {
	prime_sieve ( );
	while ( scanf ( "%d", &Case ) == 1 && Case ) {
		prime_factorize ( fabs ( Case ), opt );
		if ( Case < 0 ) printf ( "%d = -1 x", Case );
		else printf ( "%d =", Case );
		for ( int i = 0; i < opt.size ( ); i++ ) {
			for ( int j = 0; j < opt[i].second; ++j ) {
				printf ( " %d", opt[i].first );
				if ( i < opt.size() - 1 || j < opt[i].second - 1 ) printf ( " x" );
			}
		}
		printf ( "\n" );
	}
    return 0;
}