#include <cstdlib>
#include <iostream>
#include <sstream>
#include <vector>

#include "mpi.h"

using namespace std;

void set_time(int rank) {
  srand(rank);
}

int main(int argc, char** argv)
{
  if (argc != 2) {
    cerr << "Invalid count of arguments";
  } else {
    size_t n;
    stringstream convert1(argv[1]);
    if (!(convert >> n))
        n = DEFAULT_N;
    size_t a;
    stringstream convert1(argv[2]);
    if (!(convert >> a))
        a = DEFAULT_A;
    size_t b;
    stringstream convert1(argv[3]);
    if (!(convert >> b))
        b = DEFAULT_B;

    //process init
    int size, rank;
    MPI_Status status;
    MPI_Init(&argc, &argv);
    MPI_Comm_size(MPI_COMM_WORLD, &size);
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);

    set_time(rank);

    int block_size = n / size + (rank < n % size); // difference between procs <= 1 element
    bool is_wa = true;
    int cnt_in_segment = 0;

    bool curr_is_wa = true;
    int curr_cnt_in_segment = 0;

    int *arr = new int[block_size];
    for (int i = 0; i < block_size; ++i) {
        arr[i] = rand();
    }

    for (int i = 0; i < block_size; ++i) {
        if ((i > 0) && (arr[i - 1] > arr[i])) {
            curr_is_wa = false;
        }
        if (a <= arr[i] && arr[i] <= b) {
            ++curr_cnt_in_segment;
        }
    }

    int lb;
    MPI_Request requests[(rank > 0) * 2];
    if (rank > 0) {
        MPI_Isend(arr[0], 1, MPI_INT, std::max(rank - 1, 0), 0, MPI_COMM_WORLD, &requests[0]);
        MPI_Irecv(lb, 1, MPI_INT, std::max(rank - 1, 0), 0, MPI_COMM_WORLD, &requests[1]);
        if (lb > arr[0]) {
            is_wa = false;
        }
    }

    delete [] arr;
    MPI_Reduce(&curr_cnt_in_segment, &cnt_in_segment, 1, MPI_INT, MPI_SUM, 0, MPI_COMM_WORLD);
    MPI_Reduce(&curr_is_wa, &is_wa, 1, MPI_BOOL, MPI_LAND, 0, MPI_COMM_WORLD);
    MPI_Finalize();

    if (rank == 0) {
        if (is_wa) {
            cout << "Is weakly ascending. Numbers in [a:b]: " << cnt_in_segment;
        } else {
            return -1;
        }
    }

    return 0;
}