题解（模拟）

#include<iostream>
#include<cmath>
using namespace std;
int n,a[1005];
int main(){
	cin>>n;
	for(int i=n;i>=1;i--){
		cin>>a[i];
	}
	int sum;
	cin>>sum;
	if(a[n]==1){
		cout<<"x"<<"^"<<n;
	}else if(a[n]==-1){
		cout<<"-"<<"x"<<"^"<<n;
	}else{
		cout<<a[n]<<"x"<<"^"<<n;
	}
	for(int i=n-1;i>=2;i--){
		bool flag=true;
		if(a[i]==0)continue;
		if(a[i]<0){
			cout<<"-";
			a[i]=abs(a[i]);
			flag=false;
		}
		if(!flag){
			if(a[i]==1){
				cout<<"x"<<"^"<<i;
			}else{
				cout<<a[i]<<"x"<<"^"<<i;
			}
		}else{
			if(a[i]==1){
				cout<<"+"<<"x"<<"^"<<i;
			}else{
				cout<<"+"<<a[i]<<"x"<<"^"<<i;
			}
		}
	}
	if(a[1]==0){
        
    }else{
        if(a[1]==1){
		cout<<"+"<<"x";
	}else if(a[1]==-1){
		cout<<"-"<<"x";
	}else if(a[1]<0){
		cout<<"-"<<abs(a[1])<<"x";
	}else{
		cout<<"+"<<a[1]<<"x";
	}
    }
	if(sum==0){
        
    }else{
        if(sum<0){
		cout<<"-"<<abs(sum);
	}else{
		cout<<"+"<<sum;
	}
    }
	return 0;
}