a010: 因數分解 FYI: https://yunlinsong.blogspot.com/2016/01/blog-post.html

a010.cpp

#include <iostream>

using namespace std;

int main()
{
    unsigned short prime[] = {
        2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97,
        101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199,
        211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293,
        307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397,
        401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499,
        503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599,
        601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691,
        701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797,
        809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887,
        907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997
    };

    unsigned short SIZE = sizeof(prime) / sizeof(unsigned short);
    int n;
    while( cin >> n )
    {
        int temp = n;
        int counter;
        int tPrime;

        for( int i = 0; i < SIZE ; i++ )
        {
            counter = 0;
            tPrime = prime[i];
            if( tPrime * tPrime > temp )
                break;
            while( temp % tPrime == 0 )
            {
                counter++;
                temp /= tPrime;
            }

            if( counter == 0 )
                continue;

            cout << tPrime << (counter > 1? "^":"");
            if( counter >= 2 )
                cout << counter;

            if( temp != 1 )
                cout << " * ";
        }

        if( temp != 1 )
            cout << temp;

        cout << endl;
    }

    return 0;
}