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

int main(int argc, char** argv) {
    MPI_Init(&argc, &argv);
    int rank, size,pid,nprocs;
    MPI_Comm_rank(MPI_COMM_WORLD, &pid);
    MPI_Comm_size(MPI_COMM_WORLD, &nprocs);

     int s=atoi(argv[1]); 

    double* V = NULL;
    double* V_local = NULL;
    int local_size;
     int total_elements = s;
 int  base_size= total_elements / nprocs;
    int remainder = total_elements % nprocs;
    if (pid == 0) {
        V = (double*)malloc(s * sizeof(double));
     
        for (int i = 0; i <s; i++) {
            V[i] = i + 1; 
        }
    }

    //int* sendcounts = (int*)malloc(nprocs * sizeof(int));
    //int* displs = (int*)malloc(nprocs * sizeof(int));


 if (pid < remainder) {
        local_size = base_size + 1;
    } else {
        local_size = base_size;
    }
       int displs[nprocs];
    int offset = 0;

    for (int i = 0; i < nprocs; i++) {
        displs[i] = offset;
        offset +=local_size ;
  //      printf("%d \n",displs[i]);
    }

    //int *sendcounts = (int *)malloc(nprocs * sizeof(int));
int sendcounts [nprocs];
    for (int i = 0; i < nprocs; i++) {
     //sendcounts[i] = local_size; error was here fixed and replaced
       if (i < remainder) {
         sendcounts[i] = base_size + 1;
    } else {
         sendcounts[i] = base_size;
    }

    }
    local_size = sendcounts[pid];
    V_local = (double*)malloc(local_size * sizeof(double));

    MPI_Scatterv(V, sendcounts, displs, MPI_DOUBLE, V_local, local_size, MPI_DOUBLE, 0, MPI_COMM_WORLD);

    double local_sum_of_squares = 0.0;
    for (int i = 0; i < local_size; i++) {
        local_sum_of_squares += V_local[i] * V_local[i];
    }

    double global_sum_of_squares = 0.0;
    MPI_Reduce(&local_sum_of_squares, &global_sum_of_squares, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD);

    if (pid == 0) {
        double norm = sqrt(global_sum_of_squares);
        printf("The norm of the vector is: %lf\n", norm);
        
        for (int i = 0; i < s; i++) {
            V[i] /= norm;
        }

         printf("Normalized Vector:\n");
        for (int i = 0; i < s; i++) {
            printf("%f ", V[i]);
        }
        printf("\n");
    }


    
    MPI_Finalize();

    return 0;
}