2020 Multi-University Training Contest #1 1004 Distinct Sub-palindromes

2020 Multi-University Training Contest #1 1004 Distinct Sub-palindromes

题意

hdu 6754 Distinct Sub-palindromes
构造一个仅由小写字母组成的字符串，要求构成回文串数目最小的构造数目。

题解

可以发现，当n <= 3时，可以随意构造，种类数为26^n.当n>3时，abcabc……这样带循环节的肯定是回文串种类最少的，只有a、b、c三种。所以种类数为262524。（这题被mod骗了orz）

代码

#include
#define ll long long
#define INF 0x3f3f3f3f
#define LLINF 0x3f3f3f3f3f3f3f3f
#define pii pair
#define vi vector
#define SZ(x) (int)x.size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
using namespace std;
#define mod 998244353
int main(){
    int t;
    scanf("%d", &t);
    while(t--) {
        int n;
        scanf("%d", &n);
        if(n == 1) {
            printf("26\n");
        }
        else if(n == 2) {
            printf("676\n");
        }
        else if(n == 3) {
            printf("%lld\n",26 * 26 * 26);
        }
        else {
        	printf("%lld\n",26 * 25 * 24);
		}
    }
}