用c++写一遍上述代码，能直接运行

好的，下面是使用 C++ 实现的代码：

#include <iostream>
#include <vector>
#include <set>
#include <queue>

using namespace std;

int bfs(int start_x, int start_y, int end_x, int end_y) {
    queue<vector<int>> q;
    q.push({start_x, start_y, 0});  // 将起始位置加入队列
    set<pair<int, int>> visited;  // 记录已经搜索过的位置
    visited.insert({start_x, start_y});

    while (!q.empty()) {
        vector<int> cur = q.front();
        q.pop();
        int x = cur[0], y = cur[1], step = cur[2];
        if (x == end_x && y == end_y)  // 找到目标位置
            return step;
        // 尝试所有可能的移动方式，并将能够到达的位置加入队列
        for (auto [dx, dy] : vector<vector<int>>{{1, 0}, {-1, 0}, {0, 1}, {0, -1}, {2, 0}, {-2, 0}, {0, 2}, {0, -2}, {2, 2}}) {
            int nx = x + dx, ny = y + dy;
            if (visited.find({nx, ny}) == visited.end() && 1 <= nx && nx <= end_x + end_y && 1 <= ny && ny <= end_x + end_y) {
                visited.insert({nx, ny});
                q.push({nx, ny, step + 1});
            }
        }
    }
    return -1;  // 如果无法到达目标位置，返回-1
}

int backtrack(int x, int y, int end_x, int end_y, set<pair<int, int>>& visited, int step) {
    if (x == end_x && y == end_y)  // 找到目标位置，返回步数
        return step;
    int min_step = INT_MAX;
    for (auto [dx, dy] : vector<vector<int>>{{1, 0}, {-1, 0}, {0, 1}, {0, -1}, {2, 0}, {-2, 0}, {0, 2}, {0, -2}, {2, 2}}) {
        int nx = x + dx, ny = y + dy;
        if (visited.find({nx, ny}) == visited.end() && 1 <= nx && nx <= end_x + end_y && 1 <= ny && ny <= end_x + end_y) {
            visited.insert({nx, ny});
            int cur_step = backtrack(nx, ny, end_x, end_y, visited, step + 1);
            if (cur_step != -1)
                min_step = min(min_step, cur_step);
            visited.erase({nx, ny});
        }
    }
    return min_step == INT_MAX ? -1 : min_step;
}

int min_steps(int start_x, int start_y, int end_x, int end_y) {
    set<pair<int, int>> visited;
    visited.insert({start_x, start_y});
    return backtrack(start_x, start_y, end_x, end_y, visited, 0);
}

int main() {
    int start_x = 1, start_y = 1, end_x = 5, end_y = 5;
    cout << bfs(start_x, start_y, end_x, end_y) << endl;  // 输出最小步数
    cout << min_steps(start_x, start_y, end_x, end_y) << endl;
    return 0;
}

其中，backtrack 函数和之前的 Python 版本一样，使用 visited 集合记录已经访问过的位置。bfs 函数使用了一个队列和一个 visited 集合来实现广度优先搜索，代码结构和之前的 Python 版本也相似。注意，C++ 中使用 set 和 pair 来代替 Python 中的集合和元组。