IAPDemo/Libraries/red_utils/RURandomGenerator.cpp

#include "RURandomGenerator.hpp"

NS_RU_BEGIN

int RandomGenerator::generateNumber() {
    int number = (a * (long long)_seed + c) % m;
    // 更新种子值，准备下次生成
    _seed = number;
    return number;
}

void RandomGenerator::setSeed(int seed){
    _seed = seed;
}

int RandomGenerator::getSeed(){
    return _seed;
}

int RandomGenerator::randomInRange(int start, int end)
{
    CCASSERT(end >= start, "随机值范围不对");
    int len = end - start + 1;
    int value = generateNumber() % len;
    return value + start;
}

int RandomGenerator::randomIndexByWeight(const std::vector<int> &weightArray)
{
    CCASSERT(weightArray.size() > 0, "数组不能为空");
    int allWeight = 0;
    for (int i = 0; i < weightArray.size(); i++) {
        allWeight += weightArray[i];
    };
    int randomNum = randomInRange(1, allWeight);
    
    int flagWeight = 0;
    
    for (int i = 0; i < weightArray.size(); i++) {
        int tWeight = weightArray[i];
        flagWeight += tWeight;
        if (randomNum <= flagWeight) {
            return i;
        };
    };
    return 0;
}

NS_RU_END