#include <mpi.h>
#include <cstdio>

int main (int argc, char *argv[]){
  MPI_Init(&argc,&argv);


  int myproc,nbproc;

  MPI_Comm_rank(MPI_COMM_WORLD,&myproc);
  MPI_Comm_size(MPI_COMM_WORLD,&nbproc);
  
  int result = 0;
  int N = 100;
  int start = N*myproc/nbproc;
  int end = N*(myproc+1)/nbproc;
  for (int i = start ; i < end ; i++){
    result += i;
  }
  
  
  int resultReduce=0;
  MPI_Allreduce ( &result, &resultReduce, 1, MPI_INT, MPI_SUM,  MPI_COMM_WORLD);
  printf ("proc %d result %d reduce %d\n",myproc,result,resultReduce);

  MPI_Finalize();
}