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#include "mpi.h"
#include <stdio.h>
#include <stdlib.h>

#define N 8

int f(int number){
	return number*2;
}

int main(int argc, char* argv[])
{
	int rank, numprocs;
	int A[N] = {1,4,5,7,3,2,9,8};
	int B[8],C[8];
	MPI_Status status;
	
	MPI_Init(&argc, &argv);
	MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
	MPI_Comm_rank(MPI_COMM_WORLD, &rank);
	
	if(rank == 0 && N % numprocs != 0)
		MPI_Abort(MPI_COMM_WORLD, 0);
	
	int size = N / numprocs;	
	
	MPI_Scatter(A, size, MPI_INT, B, size, MPI_INT, 0, MPI_COMM_WORLD);
	
	int start = size*rank;

	for(int i = start; i < start + size ; i++)
	{
		B[i] = f(A[i]);
		printf("B[i] = %d\n", B[i]);	
	}
	
    MPI_Gather(B, size, MPI_INT, B+start , size, MPI_INT, 0, MPI_COMM_WORLD);	

	if(rank==0)
	{
	/*
		for(int i=0; i < numprocs; i++)
		{
			printf("here \n");
			MPI_Recv(B + i*size, size, MPI_INT, MPI_ANY_SOURCE, 1, MPI_COMM_WORLD, &status);
			printf("after \n");
			
		}
		*/
		printf("BEFORE LOOP \n");
		for(int i=0; i<N; i++){
			if(B[i] > B[i-1])
				printf("B[%d] = %d\n" , i, B[i]);
		}
				
	}
	// else
	// {
	// 	//MPI_Send(B, size, MPI_INT, 0, 1, MPI_COMM_WORLD);
	// 	// MPI_Gather(B, size, MPI_INT, NULL, 0, MPI_INT, 0, MPI_COMM_WORLD);	
	// }
	

	MPI_Finalize();
	return 0;


}