挑战给所有题写题解： #include<bits/stdc++.h> using namespace std; main() { int a1=100,a2=150,a3=300,a4=400,a5=1000,y; cin>>y; if(y<=a1)cout<<a1; if(y>a1&&y<=a2)cout<<a2; if(y>a2&&y<=a3)cout<<a3; if(y>a3&&y<=a4)cout<<a4; if(y>a4&&y<=a5)cout<<a5; }