还行，简单

代码：

#include <cstdio>
main(){
    int n,b,i;
    scanf("%d",&n);
    b=1;
    for(i=0;i<n;i++){
        b++;
        if(b>7){
            b=1;
        }
    }
    switch(b){
        case 1:printf("monday");break;
        case 2:printf("tuesday");break;
        case 3:printf("wednesday");break;
        case 4:printf("thursday");break;
        case 5:printf("friday");break;
        case 6:printf("saturday");break;
        case 7:printf("sunday");break;
    }
}