#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;
}