题解 | #Day of Week#

#include <stdio.h>
#include<stdbool.h>
#include<string.h>
// 判断闰年函数
bool IsRunYear(int year) {
    return (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0);
}
// 平润年各月天数
int table[2][13] = {{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
    {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
};
// 判断该年的天数
int NumberYear(int year) {
    if (IsRunYear(year) == 0)
        return 365;
    else
        return 366;
}
// 周的英文表示
char WeekTable[7][13] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
// 月的英文表示
char monthtable[12][13] = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
int main() {
    int year, month = 0, day, number = 0;
    char monthe[13];
    while ((scanf("%02d%s%04d", &day, monthe, &year)) != EOF) {
        while (strcmp(monthe, monthtable[month])) {
            month++;
        }
        month++;
        number = 0;
        int row = IsRunYear(year);
        while (year != 1) {
            number += NumberYear(--year);
        }
        for (int i = 0; i < month; i++) {
            number += table[row][i];
        }
        number += day;
        number %= 7;
        printf("%s\n", WeekTable[number]);
    }
    return 0;
}