题解

#include <iostream>
#include <vector>
#include <string>
#include <cmath>

using namespace std;

int main() {
int n;
cin >> n;
vector<int> coefficients(n + 1);
for (int i = 0; i <= n; ++i) {
cin >> coefficients[i];
}

string result;
bool first_term = true;

for (int degree = n; degree >= 0; --degree) {
    int coeff = coefficients[n - degree];
    if (coeff == 0) {
        continue;
    }

    // Handle sign
    string sign;
    if (first_term) {
        if (coeff < 0) {
            sign = "-";
        }
        first_term = false;
    } else {
        sign = (coeff > 0) ? "+" : "-";
    }

    // Handle coefficient 
    string coeff_str;
    int abs_coeff = abs(coeff);
    if (abs_coeff != 1 || degree == 0) {
        coeff_str = to_string(abs_coeff);
    }

    // Handle variable part
    string var_part;
    if (degree > 1) {
        var_part = "x^" + to_string(degree);
    } else if (degree == 1) {
        var_part = "x";
    }

    // Combine all parts
    result += sign + coeff_str + var_part;
}

cout << result << endl;
return 0;

}