题解，无注释

代码---------------------------------------------------------------------------------------------------------------------------------------------
#include<stdio.h>
int main(){

int n;      
int c;      
int num;   
int f=0;   
int a;      
scanf("%d",&n);
c = n;
while(~scanf("%d",&num)){
    if(num){
        f = 1;
        a = num < 0 ? -num : num;
        if(c^n)
            putchar(num>0 ? '+' : '-');
        else if(num<0)
            putchar('-');
        if(a^1 || !c)
            printf("%d",a);
        if(c)
            putchar('x');
        if(c>1)
            printf("^%d",c);
    }
    c--;
}
if(!f)
    putchar('0');
return 0;

}