1085 PAT単位ランキング(C言語)

設計構想:

問題からも分かるように、また並べ替え問題

です.
コンパイラ:C(gcc)

#include 
#include 
#include 

struct student{
        char id[7], school[7];
        int score;
};

struct school{
        char name[7];
        int score;
        int num;
};

int cmp_school(const void *a, const void *b)
{
        return strcmp(((struct student*)a)->school, ((struct student*)b)->school);
}

int cmp_score(const void *a, const void *b)
{
        struct school *s1 = (struct school*)a, *s2 = (struct school*)b;
        if (s1->score - s2->score)
                return s2->score - s1->score;
        else if (s1->num - s2->num)
                return s1->num - s2->num;
        else
                return strcmp(s1->name, s2->name);
}

int main()
{
        struct student stus[100001] = {0};
        struct school schs[100001] = {0};
        int n, m = 0, num = 0;
        double sum = 0;
        int i, j;
        char *tmp;

        scanf("%d", &n);
        for (i = 0; i < n; i++) {
                scanf("%s %d %s", stus[i].id, &stus[i].score, stus[i].school);
                for (tmp = stus[i].school; *tmp; tmp++)
                        *tmp = tolower(*tmp);
        }

        qsort(stus, n, sizeof(stus[0]), cmp_school);

        for (i = 0; i < n; i++) {
                switch (stus[i].id[0]) {
                case 'B':
                        sum += stus[i].score / 1.5;
                        break;
                case 'A':
                        sum += stus[i].score;
                        break;
                case 'T':
                        sum += stus[i].score * 1.5;
                        break;
                }
                num++;
                if (i == n - 1 || strcmp(stus[i].school, stus[i + 1].school)) {
                        strcpy(schs[m].name, stus[i].school);
                        schs[m].score = (int)sum;
                        schs[m].num = num;
                        sum = 0;
                        num = 0;
                        m++;
                }
        }

        qsort(schs, m, sizeof(schs[0]), cmp_score);

        printf("%d
", m);
        for (i = 0, j = 0; i < m; i++) {
                if (i > 0 && schs[i].score < schs[i - 1].score)
                        j = i;
                printf("%d %s %d %d
", j + 1, schs[i].name,
                                schs[i].score, schs[i].num);
        }

        return 0;
}