题解 | #BC76 [NOIP2008]ISBN号码#

#include <stdio.h>

int main() {
    char ISBN[14];
    scanf("%s", ISBN);
    int sum = 0, count_num = 0;
    for (int i = 0; i < 13; i++) {
        if ('0' <= ISBN[i] && ISBN[i] <= '9' && count_num < 9) {
            count_num++;
            sum += (ISBN[i]-'0') * count_num;
        }
    }
    if ((sum%11 != 10 && sum%11 == ISBN[12]-'0') || (sum%11 == 10 && ISBN[12] == 'X')) {
        printf("Right\n");
    } else {
        if (sum%11 != 10) {
            ISBN[12] = '0' + sum%11;
        } else {
            ISBN[12] = 'X';
        }
        printf("%s", ISBN);
    }
    return 0;
}