#include <iostream>  
#include <vector>  
#include <algorithm>  
#include <cmath>  
  
// 函数重载：计算三角形面积（海伦公式）  
double triangleArea(double a, double b, double c) {  
    double s = (a + b + c) / 2.0;  
    return std::sqrt(s * (s - a) * (s - b) * (s - c));  
}  
  
// 主程序  
int main() {  
    int m;  
    std::cout << "请输入木棍的数目m = ";  
    std::cin >> m;  
  
    if (m < 3) {  
        std::cout << "木棍数量不足，无法构成三角形。" << std::endl;  
        return 0;  
    }  
  
    std::vector<int> lengths(m);  
    std::cout << "请输入" << m << "根木棍长度：";  
    for (int i = 0; i < m; ++i) {  
        std::cin >> lengths[i];  
    }  
  
    // 排序木棍长度  
    std::sort(lengths.begin(), lengths.end());  
  
    double maxPerimeter = 0;  
    double maxArea = 0;  
  
    // 寻找最大周长和最大面积  
    for (int i = 0; i < m - 2; ++i) {  
        for (int j = i + 1; j < m - 1; ++j) {  
            for (int k = j + 1; k < m; ++k) {  
                if (lengths[i] + lengths[j] > lengths[k]) {  
                    double perimeter = lengths[i] + lengths[j] + lengths[k];  
                    if (perimeter > maxPerimeter) {  
                        maxPerimeter = perimeter;  
                    }  
  
                    double area = triangleArea(lengths[i], lengths[j], lengths[k]);  
                    if (area > maxArea) {  
                        maxArea = area;  
                    }  
                } else {  
                    // 由于数组已排序，可以提前终止内层循环  
                    break;  
                }  
            }  
        }  
    }  
  
    if (maxPerimeter == 0) {  
        std::cout << "无法构成三角形。" << std::endl;  
    } else {  
        std::cout << "构成的最大三角形周长为：" << maxPerimeter << std::endl;  
        std::cout << "构成的最大三角形面积为：" << maxArea << std::endl;  
    }  
  
    return 0;  
}