// SQL solution as string
const char* sqlQuery = 
"SELECT \n"
"    contest_id,\n"
"    ROUND(\n"
"        COUNT(user_id) * 100.0 / (\n"
"            SELECT COUNT(*) FROM Users\n"
"        ), 2\n"
"    ) AS percentage\n"
"FROM Register\n"
"GROUP BY contest_id\n"
"ORDER BY percentage DESC, contest_id ASC;";

// C implementation
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

typedef struct {
    int contestId;
    double percentage;
} ContestResult;

typedef struct {
    int contestId;
    int count;
} ContestCount;

int compareResults(const void* a, const void* b) {
    ContestResult* resultA = (ContestResult*)a;
    ContestResult* resultB = (ContestResult*)b;
    
    if (resultA->percentage != resultB->percentage) {
        return (resultA->percentage < resultB->percentage) ? 1 : -1;
    }
    return (resultA->contestId > resultB->contestId) ? 1 : -1;
}

int calculateContestPercentages(
    int* users, int userCount,
    int registrations[][2], int regCount,
    ContestResult* results
) {
    ContestCount contests[1000] = {0}; // Assuming max 1000 contests
    int uniqueContests = 0;
    
    // Count registrations per contest
    for (int i = 0; i < regCount; i++) {
        int contestId = registrations[i][0];
        int found = 0;
        
        for (int j = 0; j < uniqueContests; j++) {
            if (contests[j].contestId == contestId) {
                contests[j].count++;
                found = 1;
                break;
            }
        }
        
        if (!found) {
            contests[uniqueContests].contestId = contestId;
            contests[uniqueContests].count = 1;
            uniqueContests++;
        }
    }
    
    // Calculate percentages
    for (int i = 0; i < uniqueContests; i++) {
        results[i].contestId = contests[i].contestId;
        results[i].percentage = round(contests[i].count * 100.0 / userCount * 100.0) / 100.0;
    }
    
    // Sort results
    qsort(results, uniqueContests, sizeof(ContestResult), compareResults);
    
    return uniqueContests;
}