#include <cstdio>
int main() {
char t;
scanf("%c", &t);
double matrix[12][12];
for (int i = 0; i < 12; ++i)
for (int j = 0; j < 12; ++j)
scanf("%lf", &matrix[i][j]);
double sum = 0, count = 0;
for (int j = 0; j < 5; ++j)
for (int i = 1 + j; i < 11 - j; ++i) {
sum += matrix[i][j];
count++;
}
if (t == 'S') printf("%.1lf", sum);
else printf("%.1lf", sum / count);
return 0;
}
求和时只用一遍双循环
j:[0~4]
i:[1+j~11-j]