#include <stdio.h>
#include <math.h>
#include <mpi.h>

#define PI 3.141592653589793238462643

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

    int processes, pe, intervals;
    MPI_Comm_size(MPI_COMM_WORLD, &processes);
    MPI_Comm_rank(MPI_COMM_WORLD, &pe);
double time1, time2;
    if (pe == 0) {
        //printf("Number of intervals: ");
        fflush(stdout);
        //scanf("%d", &intervals);
		intervals = atoi(argv[1]);
		time1 = MPI_Wtime();
    }


    MPI_Bcast(&intervals, 1, MPI_INT, 0, MPI_COMM_WORLD);

    int count = intervals / processes;
    int start = count * pe;
    int end;

	if(pe < processes-1){
		end = count * pe + count;
	}

	if(pe == processes-1){
		end = count * pe + count + (intervals % processes);
	}

    int i;
    double subtotal, total = 0;
    for (i = start; i < end; ++i) {
        subtotal += pow(-1, i) / (2 * i + 1);
    }

	//printf("ile:   %d\n", intervals % processes);
	printf("proc:   %d\n", pe);

    MPI_Reduce(&subtotal, &total, 1, MPI_DOUBLE, MPI_SUM,
        0, MPI_COMM_WORLD);



    if (pe == 0) {
		time2 = MPI_Wtime();
        total = total * 4;
        printf("Result:   %.10lf\n", total);
        printf("Accuracy: %.10lf\n", PI - total);
        printf("Time:     %.10lf\n", time2 - time1);
    }

    MPI_Finalize();
}