C 解法, 执行用时: 1ms, 内存消耗: 256KB, 提交时间: 2020-07-07

#include<stdio.h>
#include<string.h>

int nian_fun(int n){
    switch (n){
        case 1:return 0;
        case 2:return 31;
        case 3:return 59;
        case 4:return 90;
        case 5:return 120;
        case 6:return 151;
        case 7:return 181;
        case 8:return 212;
        case 9:return 243;
        case 10:return 273;
        case 11:return 304;
        case 12:return 334;
        default:return 0;
    }
}

int runn_fun(int n){
    switch (n){
        case 1:return 0;
        case 2:return 31;
        case 3:return 60;
        case 4:return 91;
        case 5:return 121;
        case 6:return 152;
        case 7:return 182;
        case 8:return 213;
        case 9:return 244;
        case 10:return 274;
        case 11:return 305;
        case 12:return 335;
        default:return 0;
    }
}

int main(void){
    int year,month,day;
    while(scanf("%d %d %d",&year,&month,&day)!=EOF){
        if(year%4==0){
            printf("%d\n",runn_fun(month)+day);
        }
        else
            printf("%d\n",nian_fun(month)+day);
    }
}

C 解法, 执行用时: 2ms, 内存消耗: 224KB, 提交时间: 2019-04-27

#include<stdio.h>
 
int main()
{
    int a[12]={31,28,31,30,31,30,31,31,30,31,30,31};
    int year,month,day;
    int days=0,i;
    scanf("%d%d%d",&year,&month,&day);
    for(i = 0; i < month -1;i++)
        days+=a[i];
    days+=day;
    if(((year%4==0&&year%100!=0)||(year%400==0))&& month >= 3)
        days+=1;
    printf("%d\n",days);
    return 0;
}