#include <iostream>
#include <chrono>
#include <vector>
#include <random>
#include <cstdint>// ========== 大数组随机访问基准 ==========
double random_access_bench(size_t array_size_mb, size_t iterations) {size_t size = array_size_mb * 1024 * 1024 / sizeof(uint64_t); // 转换为元素个数std::vector<uint64_t> data(size);// 用随机数填充数组（同时作为伪随机跳转表）std::mt19937_64 rng(12345);for (auto& x : data) x = rng();uint64_t index = 0;uint64_t sum = 0;auto start = std::chrono::high_resolution_clock::now();for (size_t i = 0; i < iterations; ++i) {// 随机跳转：用当前值作为下一个索引index = data[index % size];sum ^= index; // 简单操作，防止优化}auto end = std::chrono::high_resolution_clock::now();std::chrono::duration<double> elapsed = end - start;// 输出结果，避免 sum 被优化std::cout << "Random access sum (dummy): " << sum << std::endl;return elapsed.count();
}// ========== 模乘运算基准 ==========
double modmul_bench(size_t iterations, uint32_t mod) {std::mt19937 rng(12345);uint32_t a = rng(), b = rng();uint64_t result = 0;auto start = std::chrono::high_resolution_clock::now();for (size_t i = 0; i < iterations; ++i) {// 执行 1ull * a * b % mod，并更新 a,b 以避免重复result ^= (1ull * a * b) % mod;a = (a + 1) % mod;b = (b + 3) % mod; // 简单变化，保持随机性}auto end = std::chrono::high_resolution_clock::now();std::chrono::duration<double> elapsed = end - start;std::cout << "Modmul result (dummy): " << result << std::endl;return elapsed.count();
}int main() {std::cout << "=== Machine Benchmark (C++14) ===\n";// 配置参数（可根据需要调整）const size_t ARRAY_MB = 64; // 数组大小 64MB（大于 L3 缓存）const size_t ACCESS_ITER = 100'000'000; // 随机访问次数const size_t MODMUL_ITER = 200'000'000; // 模乘运算次数const uint64_t MOD = 1'000'000'007; // 常用模数std::cout << "\n[Random Access Bench] array=" << ARRAY_MB << "MB, iter=" << ACCESS_ITER << "\n";double t1 = random_access_bench(ARRAY_MB, ACCESS_ITER);std::cout << "Time: " << t1 << " s\n";std::cout << "\n[Modular Multiplication Bench] iter=" << MODMUL_ITER << ", mod=" << MOD << "\n";double t2 = modmul_bench(MODMUL_ITER, MOD);std::cout << "Time: " << t2 << " s\n";return 0;
}
在某学校机器（算比较好的机器）上的测试，编译选项 g++ 1.cpp -o 1 -O2 -std=c++14。
=== Machine Benchmark (C++14) ===[Random Access Bench] array=64MB, iter=100000000
Random access sum (dummy): 8013025525817178743
Time: 0.845384 s[Modular Multiplication Bench] iter=200000000, mod=1000000007
Modmul result (dummy): 733859746
Time: 0.911595 s