[Zerojudge]a010: 因數分解

直接從2開始搜尋到輸入的值的根號，
看看能不能整除，
能整除就一直除到不能，
做完後再看看輸入的值是否已經被除到只剩下1，
如果不是，一定只是一個大於輸入的值的根號的質數，將之輸出即可。

[C++](6ms, 700KB)

	#include<iostream>
	#include<cmath>
	using namespace std;
	int main()
	{
	int x;
	while( cin >> x )
	{
	bool print = 0;
	int num;
	int limit = static_cast<int>(sqrt(x));
	for( int i = 2; i <= limit; i++ )
	{
	num = 0;
	while( x % i == 0 )
	{
	num++;
	x /= i;
	}
	if( num )
	if( print )
	{
	cout << " * " << i;
	if( num != 1 )
	cout << '^' << num;
	}
	else
	{
	print = 1;
	cout << i;
	if( num != 1 )
	cout << '^' << num;
	}
	}
	if( x != 1 )
	if( print )
	cout << " * " << x;
	else
	cout << x;
	cout << endl;
	}
	return 0;
	}

view raw Zerojudgeaa010.cpp hosted with ❤ by GitHub