PAT a1059题解

#include <cstdio>#include <cmath>const int maxn = 100010;bool isPrime(int n){if(n <= 1) return false;int sqr = (int)sqrt(1.0 * n);for(int i = 2; i <= sqr; i++){if(n % i == 0) return false;}return true;}int prime[maxn], pNum = 0;void findPrime(){for(int i = 1; i < maxn; i++){if(isPrime(i)){prime[pNum++] = i;}}}struct factor{int x, cnt;}fac[10];int main(){findPrime();int n, num = 0;scanf("%d", &n);if(n == 1) printf("1=1");else{printf("%d=", n);int sqr = (int)sqrt(1.0 * n);for(int i = 0; i < pNum && prime[i] <= sqr; i++){if(n % prime[i] == 0){fac[num].x = prime[i];fac[num].cnt = 0;while(n % prime[i] == 0){fac[num].cnt++;n /= prime[i];}num++;}if(n == 1) break;}if(n != 1){fac[num].x = n;fac[num++].cnt = 1;}for(int i = 0; i < num; i++){if(i > 0) printf("*");printf("%d", fac[i].x);if(fac[i].cnt > 1){printf("^%d", fac[i].cnt);}}}return 0;}