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

#define MAX_DIGITS_PER_VAL 3
#define NUM_STR_SIZE (MAX_DIGITS_PER_VAL + 1)

static int *vals, numVals, minVal, maxVal, count, show;
static char (*numStrTab)[NUM_STR_SIZE];

static void genNumStrTab(void) {
  numStrTab = malloc((maxVal-minVal+1)*NUM_STR_SIZE);
  char buf[5];
  for (int i=minVal; i<=maxVal; i++) {
    sprintf(buf, "%*d", NUM_STR_SIZE, i);
    memcpy(numStrTab[i-minVal], buf, NUM_STR_SIZE);
  }
}

static void printVals(void) {
  static char line[1000];
  char *p = line;
  for (int i=0; i< numVals; i++) {
    memcpy(p, numStrTab[vals[i]-minVal], NUM_STR_SIZE);
    p += NUM_STR_SIZE;
  }
  puts(line);
}

static void list1(int lowerLimit, int upperLimit, int index) {
  int start = minVal;
  if (start < lowerLimit)
    start = lowerLimit;

  if (index) {
    int end = maxVal;
    if (end > upperLimit)
      end = upperLimit;
    for (int val = start; val<=end; val++) {
      vals[index] = val;
      list1(lowerLimit+maxVal-val, upperLimit+minVal-val, index-1);
    }
  }
  else {
    vals[0] = start;
    count++;
    if (show)
      printVals();
  }
}

static void list(int targetSum) {
  count = 0;
  list1(targetSum-(numVals-1)*maxVal, targetSum-(numVals-1)*minVal, numVals-1);
  fprintf(stderr, "%d Kombinationen gefunden\n", count);
}

int main(int argc, char *argv[]) {
  numVals = strtol(argv[1], NULL, 10);
  minVal  = strtol(argv[2], NULL, 10);
  maxVal  = strtol(argv[3], NULL, 10);
  const int targetSum  = strtol(argv[4], NULL, 10);
  show = argc < 6 || !strchr(argv[5], 'o');

  genNumStrTab();
  vals = malloc(numVals*sizeof(int));
  list(targetSum);

  return 0;
}