PTA 乙级 1095 解码PAT准考证

完结撒花！！
下学期学过数据结构后会把甲级题目写掉。

#include<stdio.h>
#include<stdlib.h>
#include<math.h>

typedef struct
{
	int classroom, date, idnum, score, cnt;
	char rank, allnum[14];
}information;

int str_to_int(char *str, int N)
{
	int result = 0;

	for (int i = 0; i < N; i++)
		result += (str[i] - '0')*pow(10, N - i - 1);

	return result;
}

int cmp_1(const void *a, const void *b)
{
	information *aa = (information*)a, *bb = (information*)b;
	if (aa->score != bb->score)
		return aa->score > bb->score ? -1 : 1;
	else return strcmp(aa->allnum, bb->allnum);
}

int cmp_3(const void *a, const void *b)
{
	information *aa = (information*)a, *bb = (information*)b;
	if (aa->cnt != bb->cnt)
		return aa->cnt > bb->cnt ? -1 : 1;
	else return aa->classroom > bb->classroom ? 1 : -1;
}

int main()
{
	int N, M;

	scanf("%d %d", &N, &M);
	information *array = (information*)malloc(sizeof(information)*N);
	for (int i = 0; i < N; i++)
	{
		char num[14]; int score;
		scanf("%s %d", num, &score);
		array[i].rank = num[0], array[i].classroom = str_to_int(num + 1, 3);
		array[i].date = str_to_int(num + 4, 6), array[i].idnum = str_to_int(num + 10, 3);
		array[i].score = score, strcpy(array[i].allnum, num);
	}
	qsort(array, N, sizeof(information), cmp_1);
	for (int i = 0; i < M; i++)
	{
		int c;
		scanf("%d", &c); 
		if (c == 1)
		{
			char rank[2]; int flag = 0;
			scanf("%s", rank);
			printf("Case %d: 1 %s\n", i + 1, rank);
			for(int j=0;j<N;j++)
				if (array[j].rank == rank[0])
				{
					flag = 1;
					printf("%s %d\n", array[j].allnum, array[j].score);
				}
			if (flag == 0)
				printf("NA\n");
		}
		else if (c == 2)
		{
			int class_room, sum = 0, cnt = 0;
			scanf("%d", &class_room); 
			printf("Case %d: 2 %d\n", i + 1, class_room);
			for (int j = 0; j < N; j++)
				if (array[j].classroom == class_room)
					sum += array[j].score, cnt++;
			if(cnt!=0)
				printf("%d %d\n", cnt, sum);
			else printf("NA\n", class_room);
		}
		else if (c == 3)
		{
			int date, flag = 0;
			scanf("%d", &date);
			printf("Case %d: 3 %06d\n", i + 1, date);
			for(int j=0;j<N;j++)
				if (array[j].date == date)
				{
					flag = 1; break;
				}
			if (flag == 1)
			{
				information *class_room = (information*)malloc(sizeof(information) * 1000);
				for (int j = 0; j < 1000; j++)
					class_room[j].cnt = 0,
					class_room[j].date = 0,
					class_room[j].classroom = 0;
				for (int j = 0; j < N; j++)
					if (array[j].date == date)
						class_room[array[j].classroom].cnt++,
						class_room[array[j].classroom].date = date,
						class_room[array[j].classroom].classroom = array[j].classroom;
				qsort(class_room, 1000, sizeof(information), cmp_3);
				for (int j = 0; j < 1000; j++)
					if (class_room[j].cnt != 0)
						printf("%d %d\n", class_room[j].classroom, class_room[j].cnt);
			}
			else printf("NA\n");
		}
	}

	return 0;
}