输出一个矩阵中，由1组成的最大矩形面积，手动输入矩阵C++

以下是C++代码：

#include <iostream>
#include <stack>
#include <vector>

using namespace std;

int maximalRectangle(vector<vector<int>>& matrix) {
    int m = matrix.size();
    if (m == 0) return 0;
    int n = matrix[0].size();
    vector<int> heights(n, 0);
    int maxArea = 0;
    for (int i = 0; i < m; i++) {
        // update the heights array for each row
        for (int j = 0; j < n; j++) {
            if (matrix[i][j] == 0) {
                heights[j] = 0;
            } else {
                heights[j]++;
            }
        }
        // calculate the max area for this row
        stack<int> stk;
        for (int j = 0; j <= n; j++) {
            while (!stk.empty() && (j == n || heights[stk.top()] > heights[j])) {
                int h = heights[stk.top()];
                stk.pop();
                int w = stk.empty() ? j : j - stk.top() - 1;
                maxArea = max(maxArea, h * w);
            }
            stk.push(j);
        }
    }
    return maxArea;
}

int main() {
    vector<vector<int>> matrix;
    matrix.push_back({1, 0, 1, 0, 0});
    matrix.push_back({1, 0, 1, 1, 1});
    matrix.push_back({1, 1, 1, 1, 1});
    matrix.push_back({1, 0, 0, 1, 0});
    int area = maximalRectangle(matrix);
    cout << "The maximum rectangle area is: " << area << endl;
    return 0;
}

这个算法的时间复杂度为O(mn)，其中m和n分别是矩阵的行数和列数。