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  1. #include <bits/stdc++.h>
  2. typedef long long ll;
  3. using namespace std;
  4. int t, n, f[26], cnt;
  5. ll fact[21], ans;
  6. char s[21];
  7. int main() {
  8. 	fact[0] = 1;
  9. 	for (int i = 1; i <= 20; ++i)
  10. 		fact[i] = fact[i - 1] * i;
  11. 	scanf("%d", &t);
  12. 	while (t--) {
  13. 		memset(f, 0, sizeof f);
  14. 		scanf("%d%s", &n, s);
  15. 		for (int i = 0; i < n; ++i)
  16. 			++f[s[i] - 'a'];
  17. 		cnt = 0;
  18. 		for (int i = 0; i < 26; ++i)
  19. 			if (f[i] & 1) ++cnt;
  20. 		if (cnt > 1) puts("0");
  21. 		else {
  22. 			for (int i = 0; i < 26; ++i)
  23. 				f[i] /= 2;
  24. 			ans = fact[n / 2];
  25. 			for (int i = 0; i < 26; ++i)
  26. 				ans /= fact[f[i]];
  27. 			printf("%lld\n", ans);
  28. 		}
  29. 	}
  30. 	return 0;
  31. }
Success #stdin #stdout 0s 16064KB
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https://ideone.com/0BNI2r
language:
C++ (gcc 8.3)
created:
6 years ago
visibility:
public

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