#include <stdio.h>
#include <stdlib.h>
#include <float.h>

#define MAX_SAMPLES 1000000

int main(int argc, char *argv[]) {
    if (argc < 2) {
        fprintf(stderr, "Usage: %s number_of_bins\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    int num_bins = atoi(argv[1]);
    if (num_bins <= 0) {
        fprintf(stderr, "Number of bins must be a positive integer.\n");
        exit(EXIT_FAILURE);
    }

    int *bins = calloc(num_bins, sizeof(int));
    double *samples = malloc(MAX_SAMPLES * sizeof(double));
    if (bins == NULL || samples == NULL) {
        fprintf(stderr, "Memory allocation failed.\n");
        exit(EXIT_FAILURE);
    }

    double value, min_value = DBL_MAX, max_value = -DBL_MAX;
    int sample_count = 0;

    // Read numbers from stdin and store them into the samples array
    while (sample_count < MAX_SAMPLES && scanf("%lf", &value) != EOF) {
        samples[sample_count++] = value;
        if (value < min_value) {
            min_value = value;
        }
        if (value > max_value) {
            max_value = value;
        }
    }

    // Avoid division by zero for a single unique value
    if (min_value == max_value) {
        max_value++;
    }

    // Calculate bin width
    double range = max_value - min_value;
    double bin_width = range / num_bins;

    // Fill the bins with sample counts
    for (int i = 0; i < sample_count; i++) {
        int bin_index = (int)((samples[i] - min_value) / bin_width);
        if (bin_index == num_bins) {
            bin_index--; // Last bin includes max_value
        }
        bins[bin_index]++;
    }

    // Calculate the scaling factor based on the maximum bin count
    int max_bin_count = 0;
    for (int i = 0; i < num_bins; i++) {
        if (bins[i] > max_bin_count) {
            max_bin_count = bins[i];
        }
    }
    const int MAX_WIDTH = 50; // Adjust this to your terminal width
    double scale = max_bin_count > MAX_WIDTH ? (double)MAX_WIDTH / max_bin_count : 1.0;

    // Print the histogram
    for (int i = 0; i < num_bins; i++) {
        double bin_start = min_value + i * bin_width;
        double bin_end = bin_start + bin_width;
        printf("  [%4.1f, %4.1f): ", bin_start, bin_end);

        int marks = (int)(bins[i] * scale);
        for (int j = 0; j < marks; j++) {
            printf("▇");
        }
        printf(" %d\n", bins[i]);
    }

    // Free the allocated memory
    free(bins);
    free(samples);

    return 0;
}