题解（ACGO压缩版）

#include <bits/stdc++.h>
using namespace std;
int main() {
int n;
cin >> n;
vector<int> coeff(n + 1);
for (int i = 0; i <= n; ++i) {
cin >> coeff[i];
}
bool first = true;
for (int i = 0; i <= n; ++i) {
int c = coeff[i];
int exp = n - i;
if (c == 0) continue;
if (first) {
if (c < 0) cout << "-";
} else {
cout << (c > 0 ? "+" : "-");
}
int abs_c = abs(c);
if (abs_c != 1 || exp == 0) {
cout << abs_c;
}
if (exp >= 1) {
cout << "x";
}
if (exp > 1) {
cout << "^" << exp;
}

    first = false;
}

if (all_of(coeff.begin(), coeff.end(), [](int x){ return x == 0; })) {
    cout << "0";
}

return 0;

}