583 - Prime factors/583.cpp

   1 using namespace std;
   2 #include <algorithm>
   3 #include <iostream>
   4 #include <iterator>
   5 #include <sstream>
   6 #include <fstream>
   7 #include <cassert>
   8 #include <climits>
   9 #include <cstdlib>
  10 #include <cstring>
  11 #include <string>
  12 #include <cstdio>
  13 #include <vector>
  14 #include <cmath>
  15 #include <queue>
  16 #include <deque>
  17 #include <stack>
  18 #include <map>
  19 #include <set>
  20
  21 #define D(x) cout << #x " is " << x << endl
  22
  23 void funkie(int x){
  24   vector<int> p;
  25   while (x % 2 == 0) p.push_back(2), x /= 2;
  26   for (int d=3; 1LL*d*d <= 1LL*x; d += 2){
  27     while (x % d == 0) p.push_back(d), x /= d;
  28   }
  29   if (x > 1) p.push_back(x);
  30
  31   printf("%d", p[0]);
  32   for (int i=1; i<p.size(); ++i){
  33     printf(" x %d", p[i]);
  34   }
  35   puts("");
  36 }
  37
  38 int main(){
  39   int n;
  40   while (scanf("%d", &n)==1 && n){
  41     printf("%d = ", n);
  42     if (n < 0) printf("-1 x "), funkie(-n);
  43     else funkie(n);
  44   }
  45   return 0;
  46 }