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  1. #include <iostream>
  2. #include <cstdio>
  3. #include <cstring>
  4. #include <math.h>
  5. using namespace std;
  6.  
  7. int gcd(int u, int v) {
  8. 	if(u==v) return u;
  9. 	if(u==0) return v;
  10. 	if(v==0) return u;
  11. 	if(~u & 1) {
  12. 		if(v & 1) return gcd(u>>1, v);
  13. 		else return gcd(u>>1, v>>1)<<1;
  14. 	}
  15. 	if(~v & 1) return gcd(u, v>>1);
  16. 	if(u>v) return gcd((u-v)>>1, v);
  17. 	return gcd((v-u)>>1, u);
  18. }
  19.  
  20. int main() {
  21. 	/*int m, b[100005];
  22. 	m=100005;
  23. 	memset(b, 1, sizeof(b));
  24. 	b[0]=b[1]=0;
  25. 	for(int i=2; i<sqrt(m); i++) {
  26. 		if(!b[i]) continue;
  27. 		for(int j=i+i; j<m; j+=i) {
  28. 			if(b[j]) b[j]=0; 
  29. 		}
  30. 	}*/
  31. 	int t, n, a[100005], c;
  32. 	scanf("%d", &t);
  33. 	while(t--) {
  34. 		scanf("%d", &n);
  35. 		for(int i=0; i<n; i++) scanf("%d", &a[i]);
  36. 		c=a[0];
  37. 		for(int i=0; i<n; i++) {
  38. 			c=gcd(c, a[i]);
  39. 			if(c==1) break;
  40. 		}
  41. 		if(c==1) printf("-1\n");
  42. 		else {
  43. 			for(int i=2; i<=sqrt(c); i+=i) {
  44. 				if(c%i==0) c=i;
  45. 			}
  46. 			printf("%d\n", c);
  47. 		}
  48. 	}
  49. 	return 0;
  50. }
Success #stdin #stdout 0s 3612KB
comments (?)
stdin 
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stdout 
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https://ideone.com/rGuLtW
language:
C++ (gcc 8.3)
created:
11 years ago
visibility:
public

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