看题解？自己做！

#include <iostream> using namespace std; int main(){ int a; cin >> a; if (a<=17){ printf("%.1lf",a3.4); }else if (a<=30){ printf("%.1lf",173.4+(a-17)5.32); }else{ printf("%.1lf",173.4+13*5.32+(a-30)*7); } return 0; }