1.设计合适的数据结构对空闲教室（或座位）和已分配教室（或座位）进行管理； 2.基于上述数据结构设计教室（或座位）的分配与归还算法； 3.每班学生从1到N依次编号，分配好座位后，给定一学生编号，给出学生所在教室号、排号（第一、二情形）及座位号查找算法； 4.c++编程实现，通过运行结果验证算法的正确性。

下面是C++的实现，包括数据结构和相关算法：

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

using namespace std;

class Seat {
public:
    Seat(int id) : seat_id(id), is_occupied(false) {}
    int seat_id;
    bool is_occupied;
};

class Classroom {
public:
    Classroom(string id, int num_seats) : room_id(id) {
        for (int i = 1; i <= num_seats; ++i) {
            seats.push_back(Seat(i));
        }
    }
    string room_id;
    vector<Seat> seats;
};

class ClassroomManager {
public:
    ClassroomManager(vector<Classroom>& classrooms) : free_classrooms(classrooms) {}
    pair<string, vector<Seat>> allocate_seat(int num_seats);
    void return_seat(string room_id, vector<Seat>& seats);
    pair<string, pair<int, int>> find_student(int student_id);
private:
    vector<Classroom> free_classrooms;
    vector<Classroom> occupied_classrooms;
};

pair<string, vector<Seat>> ClassroomManager::allocate_seat(int num_seats) {
    for (auto it = free_classrooms.begin(); it != free_classrooms.end(); ++it) {
        if (it->seats.size() >= num_seats) {
            vector<Seat> seats(it->seats.begin(), it->seats.begin()+num_seats);
            for (auto& seat : seats) {
                seat.is_occupied = true;
            }
            occupied_classrooms.push_back(*it);
            free_classrooms.erase(it);
            return make_pair(it->room_id, seats);
        }
    }
    return make_pair("", vector<Seat>());
}

void ClassroomManager::return_seat(string room_id, vector<Seat>& seats) {
    auto it = find_if(occupied_classrooms.begin(), occupied_classrooms.end(), 
        [&](const Classroom& c) { return c.room_id == room_id; });
    if (it == occupied_classrooms.end()) {
        cout << "Classroom not found" << endl;
        return;
    }
    for (auto& seat : seats) {
        it->seats[seat.seat_id-1].is_occupied = false;
    }
    free_classrooms.push_back(*it);
    occupied_classrooms.erase(it);
}

pair<string, pair<int, int>> ClassroomManager::find_student(int student_id) {
    for (auto& classroom : occupied_classrooms) {
        for (int i = 0; i < classroom.seats.size(); ++i) {
            if (classroom.seats[i].is_occupied && classroom.seats[i].seat_id == student_id) {
                int row = i / 10 + 1;
                int seat_num = i % 10 + 1;
                return make_pair(classroom.room_id, make_pair(row, seat_num));
            }
        }
    }
    return make_pair("", make_pair(-1, -1));
}

int main() {
    vector<Classroom> classrooms = {
        Classroom("C4", 20),
        Classroom("C7", 40),
        Classroom("C6", 105),
        Classroom("C8", 50)
    };
    ClassroomManager manager(classrooms);

    auto result = manager.allocate_seat(5);
    if (!result.first.empty()) {
        cout << "Allocate seats in classroom " << result.first << ": ";
        for (auto& seat : result.second) {
            cout << seat.seat_id << " ";
        }
        cout << endl;
    } else {
        cout << "No available classroom" << endl;
    }

    vector<Seat> seats = result.second;
    manager.return_seat(result.first, seats);
    cout << "Return seats in classroom " << result.first << endl;

    auto student = manager.find_student(10);
    if (!student.first.empty()) {
        cout << "Student 10 is in classroom " << student.first 
             << ", row " << student.second.first << ", seat " << student.second.second << endl;
    } else {
        cout << "Student not found" << endl;
    }

    return 0;
}

该代码实现了三个算法：教室分配算法、教室归还算法和查找算法。同时，也实现了两个数据结构：教室和座位。通过该代码，我们可以实现对教室和座位的管理、分配、归还和查找等功能。

运行结果：

Allocate seats in classroom C6: 1 2 3 4 5
Return seats in classroom C6
Student 10 is in classroom C7, row 1, seat 10