Оптимизация кода

#include <iostream>
#include <time.h>
#include <stdlib.h>
 
using namespace std;
 
int GetRand(int min, int max);
void rarity();
 
int main() {
 
    srand(time(NULL));
 
    rarity();
    rarity();
    rarity();
 
    return 0;
}
 
int GetRand(int min, int max) {
 
    int num = min + rand() % (max - min + 1);
 
    return num;
}
 
void rarity() {
    
    int common, rare, myth, legend; 
    int isCommon = 0, isRare = 0, isMyth = 0, isLegend = 0; 
    int res;
 
    common = GetRand(1, 100);
    if (common <= 100) isCommon = 1;
    rare = GetRand(1, 100);
    if (rare <= 40) isRare = 2;
    myth = GetRand(1, 100);
    if (myth <= 15) isMyth = 3;
    legend = GetRand(1, 100);
    if (legend <= 5) isLegend = 4;
 
    if (isCommon > isRare) res = isCommon;
    else { res = isRare; }
    
    if (res > isMyth) res = res;
    else { res = isMyth; }
 
    if (res > isLegend) res = res;
    else { res = isLegend; }
 
    if (res == 1) cout << "Common" << endl;
    else if (res == 2) cout << "Rare" << endl;
    else if (res == 3) cout << "Myth" << endl;
    else if (res == 4) cout << "Legendary" << endl;
}

#include <random>
 
int random(int min, int max) {
    static std::random_device rd{};
    static std::mt19937 mt{rd()};
    std::uniform_int_distribution<int> dis{min, max};
    return dis(mt);
}

res = isCommon > isRare ? isCommon : isRare;