#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

#define MAX_USERS 10000
#define MAX_CHUNKS 50000

typedef struct {
    int m;
    bool users[MAX_USERS + 1][MAX_CHUNKS + 1];
    bool active_users[MAX_USERS + 1];
} FileSharing;

FileSharing* fileSharingCreate(int m) {
    FileSharing* obj = (FileSharing*)calloc(1, sizeof(FileSharing));
    obj->m = m;
    return obj;
}

int fileSharingJoin(FileSharing* obj, int* ownedChunks, int ownedChunksSize) {
    int userId = 1;
    while (userId <= MAX_USERS && obj->active_users[userId]) {
        userId++;
    }
    
    obj->active_users[userId] = true;
    for (int i = 0; i < ownedChunksSize; i++) {
        obj->users[userId][ownedChunks[i]] = true;
    }
    return userId;
}

void fileSharingLeave(FileSharing* obj, int userID) {
    obj->active_users[userID] = false;
    for (int i = 1; i <= obj->m; i++) {
        obj->users[userID][i] = false;
    }
}

int* fileSharingRequest(FileSharing* obj, int userID, int chunkID, int* returnSize) {
    int* result = (int*)malloc(MAX_USERS * sizeof(int));
    int count = 0;
    
    for (int i = 1; i <= MAX_USERS; i++) {
        if (obj->active_users[i] && obj->users[i][chunkID]) {
            result[count++] = i;
        }
    }
    
    *returnSize = count;
    return result;
}

void fileSharingFree(FileSharing* obj) {
    free(obj);
}