素因数分解 Factorize

001 void factorize( int x, vector<int> &factors ){
002     int d, q;
003     while ( x >= 4 && x % 2 == 0 ) {
004         factors.push_back(2);
005         x /= 2;
006     }
007     d = 3; q = x / d;
008     while ( q >= d ){
009         if ( x % d == 0 ) {
010             factors.push_back(d);
011             x = q;
012         } else {
013             d += 2;
014         }
015         q = x / d;
016     }
017     factors.push_back(x);
018 }