题解 | #[NOIP2008]ISBN号码#

#include <stdio.h>

int main() {
    int a, b, c;
    char d;
    scanf("%d-%d-%d-%c", &a, &b, &c, &d);
    int e = 0;
    int sum = a * 100000000 + b * 100000 + c;
    for (int i = 0; i < 9; i++) {
        int f = sum % 10;
        sum /= 10;
        e = f * (9 - i)+e;
    }
    char g = e % 11+'0';
    if(g==':')
    {
        if(d=='X')
        printf("Right\n");
        else
        printf("%d-%d-%d-%c",a,b,c,'X');
    }
    else 
    {
        if (d == g)
            printf("Right\n");
        else
            printf("%d-%d-%d-%d",a,b,c,g-'0');
        
    }
    return 0;
}