#include<bits/stdc++.h> using namespace std; double a,b,c,d; int main(){ cin>>a>>b>>c>>d; double s=ab+2ac+2bc-d; cout<<fixed<<setprecision(2)<<s11; return 0; }

本题考查有效面积的运算以及保留小数点函数的应用

C++ :

#include<iostream>
#include<iomanip>
using namespace std;

double a,b,c,k;
double cost;
int main(){
	//freopen("fen.in","r",stdin);
	//freopen("fen.out","w",stdout);
	cin >> a >> b >> c >> k;
	cost=(a*b+a*c*2+b*c*2-k)*11;
	cout << fixed << setprecision(2)<<cost;
} 

Python :

# coding=utf-8
a=input().split()
for i in range(4):
    a[i]=float(a[i])
s=a[0]*a[1]+2*a[0]*a[2]+2*a[1]*a[2]-a[3]
ans=s*11
print(format(ans,'.2f'))