CS Archives - Huahua's Tech Road

Consistent Hashing

zxi — Wed, 30 Dec 2020 23:18:37 +0000

The post Consistent Hashing appeared first on Huahua's Tech Road.

Why grid[y][x] instead of grid[x][y]?

zxi — Sat, 18 Jul 2020 00:59:50 +0000

If you don’t like grid[y][x], you can use grid[r][c] instead.

C++

#include 

using namespace std;

int main(int argc, char** argv) {
  constexpr int kRows = 2;
  constexpr int kCols = 3;
  int arr[kRows][kCols] = {{1,2,3},{4,5,6}};
  for (int r = 0; r < kRows; ++r) {
    for (int c = 0; c < kCols; ++c)
      cout << arr[r][c] << " ";
    cout << endl;
  }

  for (int r = 0; r < kRows; ++r)
    for (int c = 0; c < kCols; ++c)
      cout << &(arr[r][c]) - &(arr[0][0]) << " ";
  return 0;
}

// Output:
// 1 2 3
// 4 5 6
// 0 1 2 3 4 5

The post Why grid[y][x] instead of grid[x][y]? appeared first on Huahua's Tech Road.

Multithreading and Multiprocessing – Parallel Computing 1

zxi — Tue, 08 Jan 2019 08:42:47 +0000

Multithreading

C++

#include 

#include 

int a = 1;

void run(int s) {
  a += s;
}

int main(int argc, char** argv) {
  std::thread thread1(run, 2);
  std::thread thread2(run, 5);
  thread1.join(); 
  thread2.join();
  printf("%d\n", a);
  return 0;
}
// Output:
// 8

Multiprocessing

C++

#include 
#include 
#include 

int a = 1;
void run(bool child) { 
  a += child ? 2 : 1;
}

int main(int argc, char** argv) {
  a += 1;
  pid_t pid = fork();
  run(pid == 0);
  printf("%d\n", a);
  return 0;
}

// Output:
// 3
// 4

The post Multithreading and Multiprocessing – Parallel Computing 1 appeared first on Huahua's Tech Road.