一：功能

      对区域里面的元素进行分组，并不保证组内相等元素位置不变（稳定排序）

二：用法

#include <vector>
#include <algorithm>
#include <iostream>

struct Item {
    int id;
    bool is_selected;
};
struct Widget {
    std::vector<Item> items;
};

Widget& get_widget() {
    static Widget main_widget = {
        .items = {
            {0, false}, {1, true}, {2, false}, {3, true}, {4, false}, {5, true}
        }
    };
    return main_widget;
}

int main() {
    auto& widget = get_widget();
    std::ranges::stable_partition(widget.items, &Item::is_selected);

    for (auto &v : widget.items) {
        std::cout << v.id << " ";
    }
    std::cout << "\n";
}