题解 | #获得月份天数#

#include<stdio.h>
int main() {
    int m, n;
    while (scanf("%d %d", &n, &m) != EOF) {
        if (n % 100 != 0 && n % 4 == 0 || n % 400 == 0) {
            switch (m) {
                case 1:
                    printf("31\n");
                    break;
                case 2:
                    printf("29\n");
                    break;
                case 3:
                    printf("31\n");
                    break;
                case 4:
                    printf("30\n");
                    break;
                case 5:
                    printf("31\n");
                    break;
                case 6:
                    printf("30\n");
                    break;
                case 7:
                    printf("31\n");
                    break;
                case 8:
                    printf("31\n");
                    break;
                case 9:
                    printf("30\n");
                    break;
                case 10:
                    printf("31\n");
                    break;
                case 11:
                    printf("30\n");
                    break;
                case 12:
                    printf("31\n");
                    break;
            }

        } else {
            switch (m) {
                case 1:
                    printf("31\n");
                    break;
                case 2:
                    printf("28\n");
                    break;
                case 3:
                    printf("31\n");
                    break;
                case 4:
                    printf("30\n");
                    break;
                case 5:
                    printf("31\n");
                    break;
                case 6:
                    printf("30\n");
                    break;
                case 7:
                    printf("31\n");
                    break;
                case 8:
                    printf("31\n");
                    break;
                case 9:
                    printf("30\n");
                    break;
                case 10:
                    printf("31\n");
                    break;
                case 11:
                    printf("30\n");
                    break;
                case 12:
                    printf("31\n");
                    break;
            }


        }
    }
    return 0;
}