#include<iostream>
#include<vector>
#include<thread>
#include<mutex>

std::mutex mtx;

void computeSum(const std::vector<int>& nums, int start, int end, int& result) {
    int sum = 0;
    for(int i = start; i < end; i++) {
        sum += nums[i];
    }
    mtx.lock();
    result += sum;
    mtx.unlock();
}

int parallelSum(std::vector<int> nums, int num_threads) {
    int result = 0;
    std::vector<std::thread> threads;
    int n = nums.size();
    int chunk_size = n / num_threads;
    for(int i = 0; i < num_threads; i++) {
        int start = i * chunk_size;
        int end = (i == num_threads - 1) ? n : start + chunk_size;
        threads.push_back(std::thread(computeSum, std::ref(nums), start, end, std::ref(result)));
    }
    for(auto& th : threads) {
        th.join();
    }
    return result;
}

int main() {
    std::vector<int> nums = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    int num_threads = 4;
    std::cout << "Sum: " << parallelSum(nums, num_threads) << std::endl;
    return 0;
}

IBM✅
5/7 test case pass

Icecream Distribution
Python 3✅